Method fo recovering a cleaning agent

ABSTRACT

The invention provides a method of recovering a copper component or a manganese component from a cleaning agent containing copper oxide, a cleaning agent containing basic copper carbonate, a cleaning agent containing copper hydroxide, or a cleaning agent containing copper oxide and manganese oxide, the cleaning agents having been used for removing, through contact with a harmful gas, a phosphine contained as a harmful component in the harmful gas. Also, the invention provides a method of recovering a copper component or a manganese component from a cleaning agent containing basic copper carbonate, a cleaning agent containing copper hydroxide, or a cleaning agent containing copper oxide and manganese oxide, the cleaning agents having been used for removing, through contact with a harmful gas, a phosphine contained as a harmful component in the harmful gas. According to the present invention, the copper component and/or the manganese component can be effectively recovered from the cleaning agents in a recyclable form.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a method of recovering acleaning agent containing copper oxide as a component thereof, acleaning agent containing basic copper carbonate as a component thereof,a cleaning agent containing copper hydroxide as a component thereof, ora cleaning agent containing copper oxide and manganese oxide ascomponents thereof. More particularly, the invention relates to a methodof recovering a copper component and/or a manganese component from acleaning agent that has been used for removing a phosphine or a silanegas contained in a discharge gas from a semiconductor production step ora similar step.

[0003] 2. Background Art

[0004] In the production steps for silicon semiconductors, compoundsemiconductors, etc., phosphines and hydrides (gaseous form) such assilane and disilane are employed as source gas or doping gas.Dichlorosilane is used as a source for forming silicon nitride (Si₃N₄)film on a semiconductor substrate such as a silicon wafer. These gasesare highly harmful, and adversely affect the human body and environmentif discharged to the atmosphere without any treatment. Therefore, thegases which contain these compounds and have been used in thesemiconductor production steps must be cleaned prior to discharge to theatmosphere. In order to perform cleaning, there have conventionally beendeveloped cleaning agents for harmful gases containing as a harmfulcomponent a phosphine, a silane, a disilane, or a dichlorosilane gas.

[0005] Regarding a method of cleaning a harmful gas containing aphosphine or a silane gas, the present applicant has developed a numberof cleaning methods employing a cleaning agent containing copper oxide,or copper oxide and manganese oxide. According to one such cleaningmethod, a harmful gas containing a hydride gas such as phosphine iscleaned through contact with a cleaning agent formed of cupric oxide andan oxide of silicon and/or aluminum (Japanese Patent ApplicationLaid-Open (kokai) No. 61-129026). Japanese Patent Application Laid-Open(kokai) Nos. 62-286521 to -286525 disclose methods of cleaning a similarharmful gas through contact with a cleaning agent formed of cupric oxideand an oxide of titanium, zirconium, lanthanum, iron, cobalt, nickel,tin, lead, antimony, bismuth, vanadium, molybdenum, tungsten, niobium,or tantalum.

[0006] Japanese Patent Application Laid-Open (kokai) No. 1-254230discloses a method of cleaning a harmful gas containing arsine, silane,etc. by bringing the gas into contact with a cleaning agent formed of acomposition containing manganese dioxide, copper oxide, and cobalt oxideserving as predominant components and a silver compound. Japanese PatentApplication Laid-Open (kokai) No. 6-154535 discloses a method ofcleaning a similar gas through contact with a cleaning agent formed of acomposition containing manganese dioxide and copper oxide serving aspredominant components and a potassium component, onto which compositiona silver compound is adsorbed.

[0007] Cleaning agents containing other copper compounds include a gastreatment agent for treating a discharge gas containing a Group Vinorganic compound discharged from a production step for a Group III-Vcompound semiconductor thin film, which agent comprises a coppercompound such as basic copper carbonate (disclosed in Japanese PatentApplication Laid-Open (kokai) No. 8-59391); a gas treatment agent fortreating a discharge gas containing a Group V organic compound and aGroup V inorganic compound discharged from production step for a GroupIII-V compound semiconductor thin film, which agent is prepared bymixing basic copper carbonate and potassium permanganate with anatasetitanium oxide microparticles (disclosed in Japanese Patent ApplicationLaid-Open (kokai) No. 8-155258); and a solid removing agent forremoving, in a dry process, harmful components contained in a dischargegas such as volatile inorganic hydrides and halides, which agentcontains crystalline cupric hydroxide as a predominant reactioncomponent (disclosed in Japanese Patent Application Laid-Open (kokai)No. 6-319945).

[0008] Concerning copper compounds, manganese compounds, etc. whichserve as components of the aforementioned cleaning agents, thoseassuming the form of uniform microparticles and having a high BETspecific surface area have heretofore been developed. Methods ofproducing copper oxide of such a type are known; for example, JapanesePatent Application Laid-Open (kokai) No. 2-145422 discloses a method ofpreparing copper oxide microparticles of such a type comprising adding aneutralizing agent formed of an ammonium salt to a high-purity coppernitrate solution, to thereby form microparticles; and washing, drying,and calcining the thus-formed microparticles. Methods of producingmanganese dioxide of such a type include a method comprising mixing adilute aqueous solution of potassium permanganate, a dilute aqueoussolution of manganese sulfate, and concentrated sulfuric acid bystirring under heating so as to form precipitates, and washing anddrying the precipitates, to thereby prepare manganese dioxide of largespecific surface area. In recent years, through improvement in the shapeof copper oxide, manganese oxide, etc. which serve as components of acleaning agent in an attempt to obtain excellent characteristics as wellas through development of compositions of the cleaning agent asdescribed above, cleaning agents of more excellent cleaning power (i.e.,performance in cleaning a harmful component per unit amount of cleaningagent) have been produced.

[0009] After the aforementioned cleaning agents containing copper oxideas a component thereof, those containing basic copper carbonate as acomponent thereof, those containing copper hydroxide as a componentthereof, or those containing copper oxide and manganese oxide ascomponents thereof have been used for cleaning a gas containing aphosphine or a silane gas, the cleaning agents are deactivated throughimmersion in water or through a similar method to a safe level where thehuman body and the environment are not adversely affected, and aresubsequently treated as industrial wastes. If a copper component and amanganese component can be recovered from the industrial wastes andrecycled as components of a cleaning agent for a harmful gas, not onlyeffective use of resources but also protection of the environment couldbe attained.

[0010] However, nothing has been elucidated about the state of usedcleaning agents which have sorbed a harmful component. In addition,studies have never been conducted on, for example, reactivity of acleaning agent which has sorbed a harmful component or on possibility ofgeneration of a harmful gas during dissolution in acid or neutralizationof the cleaning agent. Thus, there has never been developed a method ofrecovering a copper component and/or a manganese component from a usedcleaning agent and of restoring activity of the components so as to makethem reusable.

SUMMARY OF THE INVENTION

[0011] The present inventors have carried out extensive studies in orderto solve the aforementioned problems, and have found that by dissolving,in an acidic solution such as sulfuric acid or nitric acid, a cleaningagent containing copper oxide, a cleaning agent containing basic coppercarbonate, a cleaning agent containing copper hydroxide, or a cleaningagent containing copper oxide and manganese oxide, the cleaning agentshaving been used for cleaning a harmful gas containing a phosphine as aharmful component, a copper component or a manganese component can bereadily separated from a phosphorus component which has been sorbed inthe cleaning agent during the course of cleaning the harmful gas. Theinventors have also found that, by dissolving, in an acidic solutionsuch as sulfuric acid or nitric acid, a cleaning agent containing basiccopper carbonate, a cleaning agent containing copper hydroxide, or acleaning agent containing copper oxide and manganese oxide, the cleaningagents having been used for cleaning a harmful gas containing a silanegas as a harmful component, a copper component or a manganese componentcan be readily separated from a silicon component which has been sorbedin the cleaning agent during the course of cleaning the harmful gas. Thepresent invention has been accomplished on the basis of these findings.

[0012] Thus, an object of the present invention is to provide a methodof effectively recovering a copper component or a manganese component,in a recyclable form, from a cleaning agent containing copper oxide, acleaning agent containing basic copper carbonate, a cleaning agentcontaining copper hydroxide, or a cleaning agent containing copper oxideand manganese oxide which has been used for removing a phosphine or asilane gas contained in a discharge gas produced during the course of asemiconductor production step or a similar step.

[0013] Accordingly, the present invention provides a method ofrecovering a cleaning agent, the cleaning agent having been used forremoving, through contact with a harmful gas, a phosphine contained as aharmful component in the harmful gas, and being at least one speciesselected from among a cleaning agent containing copper oxide as acomponent thereof, a cleaning agent containing basic copper carbonate asa component thereof, and a cleaning agent containing copper hydroxide asa component thereof, the method comprising:

[0014] immersing the cleaning agent in an acidic solution, to therebydissolve the cleaning agent;

[0015] adding to the resultant solution a precipitant for copper, tothereby cause a copper compound to precipitate;

[0016] separating a copper component from a phosphorus component whichhas been sorbed in the cleaning agent during the course of cleaning theharmful gas; and

[0017] recovering the copper component of the cleaning agent.

[0018] The present invention also provides a method of recovering acleaning agent, the cleaning agent having been used for removing,through contact with a harmful gas, a phosphine contained as a harmfulcomponent in the harmful gas, and being at least one species selectedfrom among a cleaning agent containing copper oxide as a componentthereof, a cleaning agent containing basic copper carbonate as acomponent thereof, and a cleaning agent containing copper hydroxide as acomponent thereof, the method comprising:

[0019] immersing the cleaning agent in an acidic solution, to therebydissolve the cleaning agent;

[0020] adding to the resultant solution a precipitant for phosphorus, tothereby cause a phosphorus compound to precipitate;

[0021] separating a phosphorus component which has been sorbed in thecleaning agent during the course of cleaning the harmful gas from acopper component;

[0022] adding a precipitant for copper to the solution from which thephosphorus component has been removed, to thereby cause a coppercompound to precipitate; and

[0023] recovering the copper component of the cleaning agent.

[0024] The present invention also provides a method of recovering acleaning agent, the cleaning agent having been used for removing,through contact with a harmful gas, a silane gas contained as a harmfulcomponent in the harmful gas, and being at least one species selectedfrom a cleaning agent containing basic copper carbonate as a componentthereof and a cleaning agent containing copper hydroxide as a componentthereof, the method comprising:

[0025] immersing the cleaning agent in an acidic solution, to therebytransform a copper component to a soluble copper salt and cause asilicon component to precipitate in the form of silicon oxide, thesilicon component having been sorbed in the cleaning agent during thecourse of cleaning the harmful gas;

[0026] separating the silicon component from the copper component;

[0027] adding a precipitant for copper to the solution from which thesilicon component has been removed, to thereby cause a copper compoundto precipitate; and

[0028] recovering the copper component of the cleaning agent.

[0029] The present invention also provides a method of recovering acleaning agent, the cleaning agent having been used for removing,through contact with a harmful gas, a phosphine contained as a harmfulcomponent in the harmful gas, and containing copper oxide and manganeseoxide as components thereof, the method comprising:

[0030] immersing the cleaning agent in an acidic solution, to therebydissolve the cleaning agent;

[0031] adding to the resultant solution a precipitant for copper andmanganese, to thereby cause a copper compound and a manganese compoundto precipitate;

[0032] separating a copper component and a manganese component from aphosphorus component which has been sorbed in the cleaning agent duringthe course of cleaning the harmful gas; and

[0033] recovering the copper component and the manganese component ofthe cleaning agent.

[0034] The present invention also provides a method of recovering acleaning agent, the cleaning agent having been used for removing,through contact with a harmful gas, a phosphine contained as a harmfulcomponent in the harmful gas, and containing copper oxide and manganeseoxide as components thereof, the method comprising:

[0035] immersing the cleaning agent in an acidic solution, to therebydissolve the cleaning agent;

[0036] adding to the resultant solution a precipitant for phosphorus, tothereby cause a phosphorus compound to precipitate;

[0037] separating a phosphorus component which has been sorbed in thecleaning agent during the course of cleaning the harmful gas, from acopper component and a manganese component;

[0038] adding a precipitant for copper and manganese to the solutionfrom which the phosphorus component has been removed, to thereby cause acopper compound and a manganese compound to precipitate; and

[0039] recovering the copper component and the manganese component ofthe cleaning agent.

[0040] The present invention also provides a method of recovering acleaning agent, the cleaning agent having been used for removing,through contact with a harmful gas, a silane gas contained as a harmfulcomponent in the harmful gas, and containing copper oxide and manganeseoxide as components thereof, the method comprising:

[0041] immersing the cleaning agent in an acidic solution, to therebytransform a copper component and a manganese component to a solublecopper salt and a soluble manganese salt, respectively, and cause asilicon component to precipitate in the form of silicon oxide, thesilicon component having been sorbed in the cleaning agent during thecourse of cleaning the harmful gas;

[0042] separating the silicon component from the copper component andthe manganese component;

[0043] adding a precipitant for copper and manganese to the solutionfrom which the silicon component has been removed, to thereby cause acopper compound and a manganese compound to precipitate; and

[0044] recovering the copper component and the manganese compound of thecleaning agent.

[0045] Numerous modifications and variations of the present inventionare possible in light of the spirit of the present invention, and arenot to be excluded from the scope of the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0046] The method of the present invention for recovering a cleaningagent is applied to a method of recovering a copper component and/or amanganese component from a cleaning agent containing copper oxide, acleaning agent containing basic copper carbonate, a cleaning agentcontaining copper hydroxide, or a cleaning agent containing copper oxideand manganese oxide, the cleaning agents having been used for removing,through contact with a harmful gas, a phosphine contained as a harmfulcomponent in the harmful gas. The method of the present invention forrecovering a cleaning agent is also applied to a method of recovering acopper component or a manganese component from a cleaning agentcontaining basic copper carbonate, a cleaning agent containing copperhydroxide, or a cleaning agent containing copper oxide and manganeseoxide, the cleaning agents having been used for removing, throughcontact with a harmful gas, a silane gas contained as a harmfulcomponent in the harmful gas.

[0047] The method of the present invention is drawn to a method ofrecovering a cleaning agent, the cleaning agent having been used forremoving, through contact with a harmful gas, a phosphine contained as aharmful component in the harmful gas, and being a cleaning agentcontaining copper oxide as a component thereof, a cleaning agentcontaining basic copper carbonate as a component thereof, or a cleaningagent containing copper hydroxide as a component thereof, the methodcomprising: immersing the cleaning agent in As an acidic solution, tothereby dissolve the cleaning agent; adding to the resultant solution aprecipitant for copper or a precipitant for phosphorus, to thereby causea copper compound or a phosphorus compound to precipitate; separating aphosphorus component which has been sorbed in the cleaning agent duringthe course of cleaning the harmful gas from a copper component; andrecovering the copper component of the cleaning agent.

[0048] The method of the present invention is drawn to a method ofrecovering a cleaning agent, the cleaning agent having been used forremoving, through contact with a harmful gas, a silane gas contained asa harmful component in the harmful gas, and being a cleaning agentcontaining basic copper carbonate as a component thereof or a cleaningagent containing copper hydroxide as a component thereof, the methodcomprising: immersing the cleaning agent in an acidic solution, tothereby transform a copper component to a soluble copper salt and causea silicon component to precipitate in the form of silicon oxide, thesilicon component having been sorbed in the cleaning agent during thecourse of cleaning the harmful gas; separating the silicon componentfrom the copper component; adding a precipitant for copper to thesolution from which the silicon component has been removed, to therebycause a copper compound to precipitate; and recovering the coppercomponent of the cleaning agent.

[0049] The method of the present invention is drawn to a method ofrecovering a cleaning agent, the cleaning agent having been used forremoving, through contact with a harmful gas, a phosphine contained as aharmful component in the harmful gas, and containing copper oxide andmanganese oxide as components thereof, the method comprising: immersingthe cleaning agent in an acidic solution, to thereby dissolve thecleaning agent; adding to the resultant solution a precipitant forcopper and manganese or a precipitant for phosphorus, to thereby causeeither a copper compound and a manganese compound or a phosphoruscompound to precipitate; separating a phosphorus component which hasbeen sorbed in the cleaning agent during the course of cleaning theharmful gas from a copper component and a manganese component; andrecovering the copper component and the manganese component of thecleaning agent.

[0050] The method of the present invention is drawn to a method ofrecovering a cleaning agent, the cleaning agent having been used forremoving, through contact with a harmful gas, a silane gas contained asa harmful component in the harmful gas, and containing copper oxide andmanganese oxide as components thereof, the method comprising: immersingthe cleaning agent in an acidic solution, to thereby transform a coppercomponent and a manganese component to a soluble copper salt and asoluble manganese salt, respectively, and cause a silicon component toprecipitate in the form of silicon oxide, the silicon component havingbeen sorbed in the cleaning agent during the course of cleaning theharmful gas; separating the silicon component from the copper componentand the manganese component; and recovering the copper component and themanganese compound of the cleaning agent.

[0051] The harmful gas to which the method of the present invention isto be applied is a gas containing as a harmful component at least aphosphine and/or a silane gas, such as silane or disilane. The base gasof the harmful gas is typically a gas such as nitrogen, argon, helium,or hydrogen. In the present invention, the phosphine serving as aharmful component includes phosphine, diphosphine, and alkylphosphinessuch as monomethylphosphine and t-butylphosphine, and the silane gasincludes silane, disilane, and silicon halogenides such asmonochlorosilane and dichlorosilane.

[0052] In the present invention, before use, the cleaning agent containsas a component thereof at least copper oxide, basic copper carbonate,copper hydroxide, or copper oxide and manganese oxide.

[0053] The cleaning agent containing copper oxide as a component thereofmay contain, in addition to copper oxide, at least one metal selectedfrom lithium, sodium, potassium, magnesium, calcium, strontium, barium,titanium, zirconium, lanthanum, vanadium, niobium, tantalum, molybdenum,tungsten, iron, cobalt, nickel, zinc, aluminum, silicon, tin, lead,antimony, bismuth, and copper, and/or at least one oxide of these metalother than copper oxide.

[0054] The cleaning agent containing basic copper carbonate or copperhydroxide as a component thereof may contain, in addition to basiccopper carbonate or copper hydroxide, at least one metal selected fromlithium, sodium, potassium, magnesium, calcium, strontium, barium,titanium, zirconium, lanthanum, vanadium, niobium, tantalum, molybdenum,tungsten, iron, cobalt, nickel, zinc, aluminum, silicon, tin, lead,antimony, bismuth, and copper, and/or at least one oxide of these metal.

[0055] The cleaning agent containing copper oxide and manganese oxide ascomponents thereof may contain, in addition to copper oxide andmanganese oxide, at least one metal selected from lithium, sodium,potassium, magnesium, calcium, strontium, barium, titanium, zirconium,lanthanum, vanadium, niobium, tantalum, molybdenum, tungsten, iron,cobalt, nickel, silver, platinum, ruthenium, palladium, zinc, aluminum,silicon, tin, lead, antimony, bismuth, copper, and manganese, and/or atleast one metallic compound other than copper oxide and manganese oxide.

[0056] Even when the cleaning agent to be treated in the presentinvention contains the above-described metal, metal oxide, or metalcompound, the cleaning agent typically contains, before use, copperoxide, basic copper carbonate, copper hydroxide, and/or copper oxide andmanganese oxide in a total amount of 70 wt. % or more.

[0057] In the present invention, the cleaning agent from which thecomponent is to be recovered includes the aforementioned cleaningagents; i.e., a cleaning agent containing copper oxide as a componentthereof, a cleaning agent containing basic copper carbonate as acomponent thereof, a cleaning agent containing copper hydroxide as acomponent thereof, and a cleaning agent containing copper oxide andmanganese oxide as components thereof, the agents having been used forremoving, through contact with a harmful gas, a phosphine contained as aharmful component in the harmful gas; and a cleaning agent containingbasic copper carbonate as a component thereof, a cleaning agentcontaining copper hydroxide as a component thereof, and a cleaning agentcontaining copper oxide and manganese oxide as components thereof, thecleaning agents having been used for removing, through contact with aharmful gas, a silane gas contained as a harmful component in theharmful gas.

[0058] According to the method of recovering a cleaning agent of thepresent invention, a copper component or a manganese component can berecovered, as a highly valuable component of a cleaning agent havingcleaning performance virtually equivalent to that of the unused agent,from a cleaning agent containing as a component(s) copper oxide, basiccopper carbonate, copper hydroxide, or copper oxide and manganese oxide,the cleaning agents having been used for cleaning a harmful gas.Examples of the highly valuable component include copper oxide, basiccopper carbonate, and copper hydroxide, each having a BET specificsurface area of 10 m²/g or more, and manganese oxide having a BETspecific surface area of 50 m²/g or more. From these recoveredcomponents, a cleaning agent having a BET specific surface area of 10m²/g or more can be prepared. Furthermore, according to the method ofrecovering a cleaning agent of the present invention, there can berecovered copper oxide, basic copper carbonate, or copper hydroxide,each having a BET specific surface area of 50 m²/g or more, or manganeseoxide having a BET specific surface area of 150 m²/g or more. From theabove recovered components, a cleaning agent having a BET specificsurface area of 50 m²/g or more can be prepared.

[0059] There will next be described in detail the method of recovering acopper component from a cleaning agent containing copper oxide, acleaning agent containing basic copper carbonate, or a cleaning agentcontaining copper hydroxide, the agents having been used for removing,through contact with a harmful gas, a phosphine contained as a harmfulcomponent in the harmful gas.

[0060] The cleaning agent containing copper oxide, the cleaning agentcontaining basic copper carbonate, or the cleaning agent containingcopper hydroxide, the cleaning agents having been used for removing,through contact with a harmful gas, a phosphine contained as a harmfulcomponent in the harmful gas, is removed from a cleaning column, andthen immersed in an acidic solution, to thereby dissolve in thesolution. Examples of the acidic solution to be used for dissolving thecleaning agent include inorganic acids such as sulfuric acid, nitricacid, and hydrochloric acid, and organic acids such as formic acid andacetic acid. Of these, sulfuric acid, nitric acid, and hydrochloric acidare preferred, in that these acids can readily dissolve the usedcleaning agent.

[0061] The concentration of the acidic solution and the amount of thesolution to the cleaning agent are not particularly limited, and vary inaccordance with conditions such as the type of the cleaning agent andthe type of the acidic solution. However, the acidic solution can beused under conditions such that soluble components of the cleaning agentcan readily dissolved. In the case in which sulfuric acid, nitric acid,or hydrochloric acid is used, the concentration is not particularlylimited. The concentration is preferably 5-30 wt. %, and the amount ofthe acidic solution based on 1 kg of the cleaning agent is typicallyapproximately 1-25 kg, preferably approximately 4-12 kg. The temperatureupon immersion of the cleaning agent in the acidic solution fordissolution is typically 100° C. or lower, preferably 30-80° C.

[0062] To the acidic solution in which the aforementioned cleaning agenthas been dissolved, a precipitant for copper or a precipitant forphosphorus is added, to thereby cause a copper compound or a phosphoruscompound to precipitate. Examples of the precipitant for copper includelithium hydroxide, sodium hydroxide, potassium hydroxide, ammoniumhydroxide, sodium carbonate, potassium carbonate, ammonium carbonate,sodium hydrogencarbonate, potassium hydrogencarbonate, and ammoniumhydrogencarbonate. Examples of the precipitant for phosphorus includemagnesium chloride, calcium chloride, magnesium sulfate, magnesiumnitrate, and calcium nitrate.

[0063] As described above, the copper component can be separated fromthe phosphorus component. When the copper component is separated throughprecipitation of a phosphorus compound, the copper component remainsdissolved in the solution, and therefore, a precipitant for copper mustbe added. In either case, the copper component can be precipitated inthe form of basic copper carbonate or copper hydroxide by, for example,adjusting pH during precipitation. The thus-yielded precipitate iswashed with water and dried, to thereby recover the copper component inthe form of basic copper carbonate or copper hydroxide. Alternatively,after the precipitate has been washed with water and dried, the driedproduct is calcined, to thereby recover the copper component in the formof copper oxide. The basic copper carbonate, copper hydroxide, or copperoxide which is recovered in the aforementioned manner can be providedwith a BET specific surface area equal to that of the unused cleaningagent. In the method of the present invention for recovering a cleaningagent, the component to be recovered is not limited to a coppercomponent, but may also include other metallic components in combinationwith the copper component.

[0064] There will next be described in detail the method of recovering acopper component from a cleaning agent containing basic copper carbonateor a cleaning agent containing copper hydroxide, the agents having beenused for removing, through contact with a harmful gas, a silane gascontained as a harmful component in the harmful gas.

[0065] In a manner similar to that described above, the cleaning agentcontaining basic copper carbonate or the cleaning agent containingcopper hydroxide, the cleaning agents having been used for cleaning aharmful gas containing a silane gas as a harmful component, is removedfrom a cleaning column, and then immersed in an acidic solution. Whenthe used cleaning agent is immersed in an acidic solution, the coppercomponent contained in the cleaning agent is dissolved in the acidicsolution, to thereby transform into a soluble copper salt, and a siliconcomponent which has been sorbed in the cleaning agent during the courseof a cleaning process is precipitated in the form of silicon oxide.

[0066] Examples of the acidic solution to be used for dissolving thecleaning agent include inorganic acids such as sulfuric acid, nitricacid, and hydrochloric acid, and organic acids such as formic acid andacetic acid. Of these, sulfuric acid, nitric acid, and hydrochloric acidare preferred, for the same reason as described above. The concentrationof the acidic solution and the amount of the solution to be added to thecleaning agent are adjusted in a manner similar to that of theaforementioned case. For example, in the case in which sulfuric acid,nitric acid, or hydrochloric acid is used, the concentration ispreferably 5-30 wt. %, and the amount of the acidic solution based on 1kg of the cleaning agent is typically approximately 1-25 kg, preferablyapproximately 4-12 kg. The temperature upon immersion of the cleaningagent in the acidic solution for dissolution is typically 100° C. orlower, preferably 30-80° C.

[0067] Upon or after immersion of the used cleaning agent, hydrogenperoxide may also be added to the acidic solution, to thereby promotesolidification of silicon.

[0068] To the solution containing a copper component from which solutionthe silicon component has been removed in the aforementioned manner, aprecipitant for copper is added. Examples of the precipitant for copperinclude lithium hydroxide, sodium hydroxide, potassium hydroxide,ammonium hydroxide, sodium carbonate, potassium carbonate, ammoniumcarbonate, sodium hydrogencarbonate, potassium hydrogencarbonate, andammonium hydrogencarbonate. During precipitation, by, for example,adjusting pH, the copper component can be precipitated in the form ofbasic copper carbonate or copper hydroxide. The thus-yielded precipitateis washed with water and dried, to thereby recover the copper componentin the form of basic copper carbonate or copper hydroxide.Alternatively, after the precipitate has been washed with water anddried, the dried product is calcined, to thereby recover the coppercomponent in the form of copper oxide. The basic copper carbonate,copper hydroxide, or copper oxide which is recovered in theaforementioned manner can be provided with a BET specific surface areaequal to that of the unused cleaning agent to be used for cleaning aharmful gas containing a silane gas. In the method of the presentinvention for recovering a cleaning agent, the component to be recoveredis not limited to a copper component, but may also include othermetallic components in combination with the copper component.

[0069] There will next be described in detail the method of recovering acopper component and a manganese component from a cleaning agentcontaining copper oxide and manganese oxide, the cleaning agent havingbeen used for removing, through contact with a harmful gas, a phosphinecontained as a harmful component in the harmful gas.

[0070] In a manner similar to that described above, the cleaning agentcontaining copper oxide and manganese oxide, the cleaning agent havingbeen used for cleaning a harmful gas containing a phosphine as a harmfulcomponent, is removed from a cleaning column, and then immersed in anacidic solution, to thereby dissolve in the solution. Examples of theacidic solution to be used for dissolving the cleaning agent includeinorganic acids such as sulfuric acid, nitric acid, and hydrochloricacid, and organic acids such as formic acid and acetic acid. Of these,sulfuric acid, nitric acid, and hydrochloric acid are preferred, for thesame reason as described above.

[0071] The concentration of the acidic solution, the amount of thesolution to be added to the cleaning agent, and the temperature uponimmersion of the cleaning agent in the acidic solution are adjusted in amanner similar to that of the aforementioned case. Since manganese issomewhat difficult to dissolve in an acidic solution, a reducing agentis preferably added to the solution, upon or after immersion of thecleaning agent in the solution, to thereby enhance solubility ofmanganese in the solution. Examples of the reducing agent includehydrogen peroxide, formic acid, acetic acid, and sulfurous acid.

[0072] To the acidic solution in which the cleaning agent has beendissolved in a previously mentioned manner, a precipitant for copper andmanganese or a precipitant for phosphorus is added, to thereby causeeither a copper component and a manganese component or a phosphoruscompound to precipitate in the form of copper compound and manganesecompound or phosphorus compound. Thus, the copper component and themanganese component are isolated from the phosphorus component.Precipitants similar to those employed for copper can be used asprecipitants for copper and manganese.

[0073] As described above, the copper component and the manganesecomponent can be separated from the phosphorus component. When thecopper component and the manganese component are separated throughprecipitation of a phosphorus compound, the copper component and themanganese component remain dissolved in the solution, and therefore, aprecipitant for copper and manganese must be added. In either case, thecopper component and the manganese component can both be precipitated inthe form of basic copper carbonate and manganese carbonate by, forexample, adjusting pH during precipitation. The thus-yielded precipitateis washed with water, dried, and calcined, to thereby recover the coppercomponent and the manganese component in the form of a mixture of copperoxide and manganese oxide. The copper oxide and manganese oxide whichare recovered in the aforementioned manner can be provided with a BETspecific surface area equal to that of the unused cleaning agent. In themethod of the present invention for recovering a cleaning agent, thecomponent to be recovered is not limited to a copper component and amanganese component, but may also include other metallic components incombination with the copper component and the manganese compound.

[0074] There will next be described in detail the method of recovering acopper component and a manganese component from a cleaning agentcontaining copper oxide and manganese oxide, the cleaning agent havingbeen used for removing, through contact with a harmful gas, a silane gascontained as a harmful component in the harmful gas.

[0075] In a manner similar to that described above, the cleaning agentcontaining copper oxide and manganese oxide, the cleaning agent havingbeen used for cleaning a harmful gas containing a silane gas as aharmful component, is removed from a cleaning column, and then immersedin an acidic solution. Examples of the acidic solution to be used fordissolving the cleaning agent include inorganic acids such as sulfuricacid, nitric acid, and hydrochloric acid, and organic acids such asformic acid and acetic acid. Of these, sulfuric acid, nitric acid, andhydrochloric acid are preferred, for the same reason as described above.

[0076] The concentration of the acidic solution, the amount of thesolution to be added to the cleaning agent, and the temperature uponimmersion of the cleaning agent in the acidic solution are adjusted in amanner similar to that of the aforementioned case. Since manganese issomewhat difficult to dissolve in an acidic solution, a reducing agentis preferably added to the solution, upon or after immersion of thecleaning agent in the solution, to thereby enhance solubility ofmanganese in the solution. Examples of the reducing agent includehydrogen peroxide, formic acid, acetic acid, and sulfurous acid. Ofthese, hydrogen peroxide is preferred, in that hydrogen peroxide canpromote solidification of silicon as well as solubility of manganese inan acidic solution.

[0077] By immersing the cleaning agent in the acidic solution, copperand manganese form a soluble copper salt and a soluble manganese salt,respectively, while silicon which has been sorbed in the cleaning agentduring the course of cleaning the harmful gas is precipitated in theform of silicon oxide.

[0078] To the solution containing a copper component and a manganesecomponent, the silicon component having been removed from the solutionin the aforementioned manner, a precipitant for copper and manganese isadded, to thereby cause a copper compound and a manganese compound toprecipitate. Examples of the precipitant for copper and manganeseinclude lithium hydroxide, sodium hydroxide, potassium hydroxide,ammonium hydroxide, sodium carbonate, potassium carbonate, ammoniumcarbonate, sodium hydrogencarbonate, potassium hydrogencarbonate, andammonium hydrogencarbonate. During precipitation, by, for example,adjusting pH, the copper component and the manganese component can beprecipitated in the form of basic copper carbonate and manganesecarbonate, respectively. The thus-yielded precipitate is washed withwater, dried, and calcined, to thereby recover the copper component andthe manganese component in the form of a mixture of copper oxide andmanganese oxide. The copper oxide and manganese oxide which arerecovered in the aforementioned manner can be provided with a BETspecific surface area equal to that of the unused cleaning agent. In themethod of the present invention for recovering a cleaning agent, thecomponent to be recovered is not limited to a copper component and amanganese component, but may also include other metallic components incombination with the copper component and the manganese component.

[0079] According to the method of the present invention for recovering acleaning agent, a copper component or a manganese component can beeffectively recovered, in a recyclable form, from a cleaning agentcontaining copper oxide as a component thereof, a cleaning agentcontaining basic copper carbonate as a component thereof, a cleaningagent containing copper hydroxide as a component thereof, or a cleaningagent containing copper oxide and manganese oxide as components thereof,the cleaning agents having been used for removing a phosphine containedin a discharge gas produced during a semiconductor production step or asimilar step. Also, a copper component or a manganese component can beeffectively recovered, in a recyclable form, from a cleaning agentcontaining basic copper carbonate as a component thereof, a cleaningagent containing copper hydroxide as a component thereof, or a cleaningagent containing copper oxide and manganese oxide as components thereof,the cleaning agents having been used for removing a silane gas containedin a discharge gas produced during a semiconductor production step or asimilar step.

[0080] The present invention will next be described in more detail byway of examples, which should not be construed as limiting the inventionthereto.

EXAMPLE 1

[0081] Preparation of Cleaning Agent Containing Copper Oxide

[0082] Commercial copper sulfate pentahydrate (1.5 kg) was dissolved inion-exchange water (5 L). To the resultant solution, a 15 wt. % aqueoussolution (4.3 kg) of sodium carbonate was added, to thereby cause acopper component to precipitate. The resultant precipitate was filtered,washed with water, and kneaded with a 10 wt. % alumina sol (200 g) bymeans of a kneader. The resultant mixture was dried at 120° C. andcalcined at 350° C., to thereby prepare a cleaning agent raw materialcomprising cupric oxide (96 wt. %) and aluminum oxide (4 wt. %). Thethus-prepared raw material was formed into pellets (diameter: 6 mm,height: 6 mm). The pellets were milled, and, after having passed 12-meshto 28-mesh sieves, the product was employed as a cleaning agent A. TheBET specific surface area of the cleaning agent A, as measured by meansof a gas adsorption amount measurement apparatus (Autosorb 3B, productof Yuasa Ionics), was 70 m²/g.

[0083] Cleaning Harmful Gas Containing Phosphine

[0084] The cleaning agent A was charged into a cleaning column (insidediameter: 40 mm) made of hard glass such that the pack length wasadjusted to 100 mm. Into this cleaning column, a dry-nitrogen-based gascontaining phosphine (10,000 ppm) as a harmful component was caused topass at a flow rate of 2,000 ml/min (superficial velocity: 2.65 cm/sec)at a temperature of 20° C. under atmospheric pressure. During passage ofthe gas, a portion of the gas flowing from the outlet of the cleaningcolumn was aspirated into a detection tube (Phosphine 7 L, product ofGastech, detection limit: 0.15 ppm), and the time elapsed untildetection of phosphine (effective treatment time) was measured, tothereby obtain the amount (L) of phosphine removed per liter (L) of acleaning agent (cleaning performance). The results are shown in Table 1.

[0085] Recovery of Copper Component from Cleaning Agent

[0086] The cleaning agent A, having been used in a manner similar tothat employed in the aforementioned cleaning of a harmful gas containingphosphine, was collected in an amount of 500 g, and the collectedcleaning agent was immersed in a 10 wt. % aqueous sulfuric acid solution(6 kg) for dissolution. Insoluble components were removed from the acidsolution through filtration, and a 15 wt. % aqueous solution (4.3 kg) ofsodium carbonate serving as a precipitant for copper was added to thefiltrate, to thereby cause a copper component to precipitate. Theresultant precipitate was filtered, washed with water, and kneaded withaluminum oxide (16 g) by means of a kneader. The resultant mixture wasdried at 120° C. and calcined at 350° C., to thereby recover the coppercomponent in the form of cupric oxide. The thus-recovered matter wasfound to comprise cupric oxide (96 wt. %) and aluminum oxide (4 wt. %).The recovered matter was further formed into pellets (diameter: 6 mm,height: 6 mm). The pellets were milled, and, after having passed 12-meshto 28-mesh sieves, the milled product was employed as a cleaning agentA′. The BET specific surface area of the cleaning agent A′ was found tobe 72 m²/g.

[0087] In the aforementioned procedure, the precipitate was filtered,washed with water, and dried, to thereby recover basic copper carbonate.The BET specific surface area of the basic copper carbonate, as measuredby means of a gas adsorption amount measurement apparatus, was 60 m²/g.The obtained basic copper carbonate was calcined, to thereby recovercupric oxide having a BET specific surface area of 69 m²/g. In order torecover copper hydroxide, the aforementioned procedure was repeated,except that a 4.1 wt. % aqueous solution (6.0 kg) of sodium hydroxidewas used as a precipitant for copper instead of the aqueous solution ofsodium carbonate, to thereby cause a copper component to precipitate.The precipitate was filtered, washed with water, and dried at 120° C.,to thereby recover the copper component in the form of copper hydroxide.The BET specific surface area of the recovered copper hydroxide wasfound to be 42 m²/g.

[0088] Cleaning Harmful Gas Containing Phosphine by Use of RegeneratedCleaning Agent

[0089] In a manner similar to that employed in the cleaning of a harmfulgas by means of the cleaning agent A, the cleaning agent A′ was chargedinto a cleaning column (inside diameter: 40 mm) made of hard glass suchthat the pack length was adjusted to 100 mm. Into this cleaning column,a dry-nitrogen-based gas containing phosphine (10,000 ppm) as a harmfulcomponent was caused to pass at a flow rate of 2,000 ml/min (superficialvelocity: 2.65 cm/sec) at a temperature of 20° C. under atmosphericpressure, to thereby perform a cleaning test. The measurement results interms of cleaning performance of the cleaning agent A′ are shown inTable 1.

Example 2

[0090] Preparation of Cleaning Agent Containing Copper Oxide

[0091] Commercial copper sulfate pentahydrate (1.5 kg) was dissolved inion-exchange water (5 L). To the resultant solution, a 15 wt. % aqueoussolution (4.3 kg) of sodium carbonate was added, to thereby cause acopper component to precipitate. The resultant precipitate was filtered,washed with water, and kneaded with zirconium oxide (25 g) by means of akneader. The resultant mixture was dried at 120° C. and calcined at 350°C., to thereby prepare a cleaning agent raw material comprising cupricoxide (95 wt. %) and zirconium oxide (5 wt. %). The thus-prepared rawmaterial was formed into pellets (diameter: 6 mm, height: 6 mm). Thepellets were milled, and, after having passed 12-mesh to 28-mesh sieves,the product was employed as a cleaning agent B. The BET specific surfacearea of the cleaning agent B was found to be 65 m²/g.

[0092] Cleaning Harmful Gas Containing Phosphine

[0093] The procedure of Example 1 was repeated, except that the cleaningagent B was used instead of the cleaning agent A employed in “CleaningHarmful Gas Containing Phosphine” of Example 1, to thereby clean aharmful gas containing phosphine. The measurement results in terms ofcleaning performance of the cleaning agent B are shown in Table 1.

[0094] Recovery of Copper Component from Cleaning Agent

[0095] The cleaning agent B, having been used in a manner similar tothat employed in the aforementioned cleaning of a harmful gas containingphosphine, was collected in an amount of 500 g, and the collectedcleaning agent was immersed in a 10 wt. % aqueous sulfuric acid solution(6 kg) for dissolution. Insoluble components were removed from the acidsolution through filtration, and a 15 wt. % aqueous solution (4.3 kg) ofsodium carbonate serving as a precipitant for copper was added to thefiltrate, to thereby cause a copper component to precipitate. Theresultant precipitate was filtered, washed with water, and kneaded withzirconium oxide (20 g) by means of a kneader. The resultant mixture wasdried at 120° C. and calcined at 350° C., to thereby recover the coppercomponent in the form of cupric oxide. The thus-recovered matter wasfound to comprise cupric oxide (95 wt. %) and zirconium oxide (5 wt. %).The recovered matter was further formed into pellets (diameter: 6 mm,height: 6 mm). The pellets were milled, and, after having passed 12-meshto 28-mesh sieves, the milled product was employed as a cleaning agentB′. The BET specific surface area of the cleaning agent B′ was found tobe 68 m²/g.

[0096] Cleaning Harmful Gas Containing Phosphine by Use of RegeneratedCleaning Agent

[0097] The procedure of Example 1 was repeated, except that the cleaningagent B′ was used instead of the cleaning agent A′ employed in “CleaningHarmful Gas Containing Phosphine by Use of Regenerated Cleaning Agent”of Example 1, to thereby perform a cleaning test for a harmful gascontaining phosphine. The measurement results in terms of cleaningperformance of the cleaning agent B′ are shown in Table 1.

Example 3

[0098] Preparation of Cleaning Agent Containing Copper Oxide

[0099] Commercial copper sulfate pentahydrate (1.5 kg) was dissolved inion-exchange water (5 L). To the resultant solution, a 15 wt. % aqueoussolution (4.3 kg) of sodium carbonate was added, to thereby cause acopper component to precipitate. The resultant precipitate was filtered,washed with water, and kneaded with zinc oxide (20 g) by means of akneader. The resultant mixture was dried at 120° C. and calcined at 350°C., to thereby prepare a cleaning agent raw material comprising cupricoxide (96 wt. %) and zinc oxide (4 wt. %). The thus-prepared rawmaterial was formed into pellets (diameter: 6 mm, height: 6 mm). Thepellets were milled, and, after having passed 12-mesh to 28-mesh sieves,the product was employed as a cleaning agent C. The BET specific surfacearea of the cleaning agent C was found to be 80 m²/g.

[0100] Cleaning Harmful Gas Containing t-Butylphosphine

[0101] The procedure of Example 1 was repeated, except that a gascontaining t-butylphosphine (10,000 ppm) was used instead of a gascontaining phosphine (10,000 ppm) and that the cleaning agent C was usedinstead of the cleaning agent A employed in “Cleaning Harmful GasContaining Phosphine” of Example 1, to thereby clean a harmful gascontaining t-butylphosphine. The measurement results in terms ofcleaning performance of the cleaning agent C are shown in Table 1.

[0102] Recovery of Copper Component from Cleaning Agent

[0103] The cleaning agent C, having been used in a manner similar tothat employed in the aforementioned cleaning of a harmful gas containingt-butylphosphine, was collected in an amount of 500 g, and the collectedcleaning agent was immersed in a 10 wt. % aqueous nitric acid solution(7.6 kg) for dissolution. Insoluble components were removed from theacid solution through filtration, and a 15 wt. % aqueous solution (3.2kg) of sodium hydroxide serving as a precipitant for copper was added tothe filtrate, to thereby cause a copper component to precipitate. Theresultant precipitate was filtered, washed with water, and kneaded withzinc oxide (16 g) by means of a kneader. The resultant mixture was driedat 120° C. and calcined at 350° C., to thereby recover the coppercomponent in the form of cupric oxide. The thus-recovered matter wasfound to comprise cupric oxide (96 wt. %) and zinc oxide (4 wt. %). Therecovered matter was further formed into pellets (diameter: 6 mm,height: 6 mm). The pellets were milled, and, after having passed 12-meshto 28-mesh sieves, the product was employed as a cleaning agent C′. TheBET specific surface area of the cleaning agent C′ was found to be 75m²/g.

[0104] Cleaning Harmful Gas Containing t-Butylphosphine by Use ofRegenerated Cleaning Agent

[0105] The procedure of Example 1 was repeated, except that a gascontaining t-butylphosphine (10,000 ppm) was used instead of a gascontaining phosphine (10,000 ppm) and that the cleaning agent C′ wasused instead of the cleaning agent A′ employed in “Cleaning Harmful GasContaining Phosphine by Use of Regenerated Cleaning Agent” of Example 1,to thereby perform a cleaning test for a harmful gas containingt-butylphosphine. The measurement results in terms of cleaningperformance of the cleaning agent C′ are shown in Table 1.

Example 4

[0106] Preparation of Cleaning Agent Containing Copper Oxide

[0107] Commercial copper sulfate pentahydrate (1.5 kg) was dissolved inion-exchange water (5 L). To the resultant solution, a 15 wt. % aqueoussolution (4.3 kg) of sodium carbonate was added, to thereby cause acopper component to precipitate. The resultant precipitate was filtered,washed with water, and kneaded with silicon dioxide (30 g) by means of akneader. The resultant mixture was dried at 120° C. and calcined at 350°C., to thereby prepare a cleaning agent raw material comprising cupricoxide (94 wt. %) and silicon dioxide (6 wt. %). The thus-prepared rawmaterial was formed into pellets (diameter: 6 mm, height: 6 mm). Thepellets were milled, and, after having passed 12-mesh to 28-mesh sieves,the product was employed as a cleaning agent D. The BET specific surfacearea of the cleaning agent D was found to be 70 m²/g.

Cleaning Harmful Gas Containing Phosphine

[0108] The procedure of Example 1 was repeated, except that the cleaningagent D was used instead of the cleaning agent A employed in “CleaningHarmful Gas Containing Phosphine” of Example 1, to thereby clean aharmful gas containing phosphine. The measurement results in terms ofcleaning performance of the cleaning agent D are shown in Table 1.

[0109] Recovery of Copper Component from Cleaning Agent

[0110] The cleaning agent D, having been used in a manner similar tothat employed in the aforementioned cleaning of a harmful gas containingphosphine, was collected in an amount of 500 g, and the collectedcleaning agent was immersed in a 10 wt. % aqueous sulfuric acid solution(6 kg) for dissolution. Insoluble components were removed from the acidsolution through filtration, and a 15 wt. % aqueous solution (1.5 kg) ofmagnesium sulfate serving as a precipitant for phosphorus was added tothe filtrate, to thereby cause a phosphorus component to precipitate.The resultant precipitate was removed through filtration. A 15 wt. %aqueous solution (4.3 kg) of sodium carbonate serving as a precipitantfor copper was added to the resultant filtrate, to thereby cause acopper component to precipitate. The obtained precipitate was filtered,washed with water, and kneaded with silicon dioxide (30 g) by means of akneader. The resultant mixture was dried at 120° C. and calcined at 350°C., to thereby recover the copper component in the form of cupric oxide.The thus-recovered matter was found to comprise cupric oxide (94 wt. %)and silicon dioxide (6 wt. %). The recovered matter was further formedinto pellets (diameter: 6 mm, height: 6 mm). The pellets were milled,and, after having passed 12-mesh to 28-mesh sieves, the product wasemployed as a cleaning agent D′. The BET specific surface area of thecleaning agent D′ was found to be 68 m²/g.

[0111] Cleaning Harmful Gas Containing Phosphine by Use of RegeneratedCleaning Agent

[0112] The procedure of Example 1 was repeated, except that the cleaningagent D′ was used instead of the cleaning agent A′ employed in “CleaningHarmful Gas Containing Phosphine by Use of Regenerated Cleaning Agent”of Example 1, to thereby perform a cleaning test for a harmful gascontaining phosphine. The measurement results in terms of cleaningperformance of the cleaning agent D′ are shown in Table 1.

Example 5

[0113] Preparation of Cleaning Agent Containing Copper Oxide andManganese Oxide

[0114] Commercial copper sulfate pentahydrate (0.5 kg) and manganesesulfate heptahydrate (1.4 kg) were dissolved in ion-exchange water (5L). To the resultant solution, a 15 wt. % aqueous solution (4.3 kg) ofsodium carbonate was added, to thereby cause a copper component and amanganese component to precipitate. The resultant precipitate wasfiltered, washed with water, and kneaded with 10 wt. % alumina sol (380g) by means of a kneader. The resultant mixture was dried at 120° C., tothereby prepare a cleaning agent raw material comprising cupric oxide(25 wt. %), manganese dioxide (69 wt. %), and aluminum oxide (6 wt. %).The thus-prepared raw material was formed into pellets (diameter: 6 mm,height: 6 mm). The pellets were milled, and, after having passed 12-meshto 28-mesh sieves, the product was employed as a cleaning agent E. TheBET specific surface area of the cleaning agent E was found to be 165m²/g.

[0115] Cleaning Harmful Gas Containing Phosphine

[0116] The procedure of Example 1 was repeated, except that the cleaningagent E was used instead of the cleaning agent A employed in “CleaningHarmful Gas Containing Phosphine” of Example 1, to thereby clean aharmful gas containing phosphine. The measurement results in terms ofcleaning performance of the cleaning agent E are shown in Table 1.

[0117] Recovery of Copper Component and Manganese Component fromCleaning Agent

[0118] The cleaning agent E, having been used in a manner similar tothat employed in the aforementioned cleaning of a harmful gas containingphosphine, was collected in an amount of 500 g, and the collectedcleaning agent was immersed in a mixture containing a 10 wt. % aqueoussulfuric acid solution (5.6 kg) and a 30 wt. % aqueous hydrogen peroxidesolution (0.2 kg) for dissolution. Insoluble components were removedfrom the mixture solution through filtration, and a 15 wt. % aqueoussolution (4 kg) of sodium carbonate serving as a precipitant for copperand manganese was added to the filtrate, to thereby cause a coppercomponent and a manganese component to precipitate. The obtainedprecipitate was filtered, washed with water, and kneaded with aluminumoxide (24 g) by means of a kneader. The resultant mixture was dried at120° C., to thereby recover the copper component and the manganesecomponent in the form of cupric oxide and manganese dioxide,respectively. The thus-recovered matter was found to comprise cupricoxide (25 wt. %), manganese dioxide (69 wt. %), and aluminum oxide (6wt. %). In the above operation, if no aluminum oxide is added to theprecipitate containing the copper component and the manganese component,only cupric oxide and manganese oxide can be recovered. The recoveredmatter was further formed into pellets (diameter: 6 mm, height: 6 mm).The pellets were milled, and, after having passed 12-mesh to 28-meshsieves, the product was employed as a cleaning agent E′. The BETspecific surface area of the cleaning agent E′ was found to be 170 m²/g.

[0119] Cleaning Harmful Gas Containing Phosphine by Use of RegeneratedCleaning Agent

[0120] The procedure of Example 1 was repeated, except that the cleaningagent E′ was used instead of the cleaning agent A′ employed in “CleaningHarmful Gas Containing Phosphine by Use of Regenerated Cleaning Agent”of Example 1, to thereby perform a cleaning test for a harmful gascontaining phosphine. The measurement results in terms of cleaningperformance of the cleaning agent E′ are shown in Table 1.

Example 6

[0121] Preparation of Cleaning Agent Containing Copper Oxide andManganese Oxide

[0122] The procedure of Example 5 was repeated, to thereby prepare acleaning agent F comprising cupric oxide (25 wt. %), manganese dioxide(69 wt. %), and aluminum oxide (6 wt. %). The BET specific surface areaof the cleaning agent F was found to be 163 m²/g.

[0123] Cleaning Harmful Gas Containing Phosphine

[0124] The procedure of Example 1 was repeated, except that the cleaningagent F was used instead of the cleaning agent A employed in “CleaningHarmful Gas Containing Phosphine” of Example 1, to thereby clean aharmful gas containing phosphine. The measurement results in terms ofcleaning performance of the cleaning agent F are shown in Table 1.

[0125] Recovery of Copper Component and Manganese Component fromCleaning Agent

[0126] The cleaning agent F, having been used in a manner similar tothat employed in the aforementioned cleaning of a harmful gas containingphosphine, was collected in an amount of 500 g, and the collectedcleaning agent was immersed in a mixture containing a 10 wt. % aqueoussulfuric acid solution (5.6 kg) and a 30 wt. % aqueous hydrogen peroxidesolution (0.2 kg) for dissolution. Insoluble components were removedfrom the mixture solution through filtration, and a 15 wt. % aqueoussolution (1.5 kg) of magnesium sulfate serving as a precipitant forphosphorus was added to the filtrate, to thereby cause a phosphoruscomponent to precipitate. The precipitate of the phosphorus componentwas removed through filtration. A 15 wt. % aqueous solution (4 kg) ofsodium carbonate serving as a precipitant for copper and manganese wasadded to the resultant filtrate, to thereby cause a copper component anda manganese component to precipitate. The obtained precipitate wasfiltered, washed with water, and kneaded with aluminum oxide (24 g) bymeans of a kneader. The resultant mixture was dried at 120° C., tothereby recover the copper component and the manganese component in theform of cupric oxide and manganese dioxide, respectively. Thethus-recovered matter was found to comprise cupric oxide (25 wt. %),manganese dioxide (69 wt. %), and aluminum oxide (6 wt. %). Therecovered matter was further formed into pellets (diameter: 6 mm,height: 6 mm). The pellets were milled, and, after having passed 12-meshto 28-mesh sieves, the product was employed as a cleaning agent F′. TheBET specific surface area of the cleaning agent F′ was found to be 167m²/g.

[0127] Cleaning Harmful Gas Containing Phosphine by Use of RegeneratedCleaning Agent

[0128] The procedure of Example 1 was repeated, except that the cleaningagent F′ was used instead of the cleaning agent A′ employed in “CleaningHarmful Gas Containing Phosphine by Use of Regenerated Cleaning Agent”of Example 1, to thereby perform a cleaning test for a harmful gascontaining phosphine. The measurement results in terms of cleaningperformance of the cleaning agent F′ are shown in Table 1.

Example 7

[0129] Preparation of Cleaning Agent Containing Copper Oxide andManganese Oxide

[0130] The procedure of Example 5 was repeated, to thereby prepare acleaning agent G comprising cupric oxide (25 wt. %), manganese dioxide(69 wt. %), and aluminum oxide (6 wt. %). The BET specific surface areaof the cleaning agent G was found to be 166 m²/g.

[0131] Cleaning Harmful Gas Containing Silane

[0132] The cleaning agent G was charged into a cleaning column (insidediameter: 40 mm) made of hard glass such that the pack length wasadjusted to 100 mm. Into this cleaning column, a dry-nitrogen-based gascontaining silane (10,000 ppm) as a harmful component was caused to passat 20° C. under atmospheric pressure at a flow rate of 2,000 ml/min(superficial velocity: 2.65 cm/sec). During passage of the gas, aportion of the gas flowing from the outlet of the cleaning column wasaspirated into a detection tube (Silane S, product of Komyo RikagakuKogyo, detection limit: 0.5 ppm), and the time elapsed until detectionof silane (effective treatment time) was measured, to thereby obtain theamount (L) of silane removed per liter (L) of a cleaning agent (cleaningperformance). The results are shown in Table 1.

[0133] Recovery of Copper Component and Manganese Component fromCleaning Agent

[0134] The cleaning agent G, having been used in a manner similar tothat employed in the aforementioned cleaning of a harmful gas containingsilane, was collected in an amount of 500 g, and the collected cleaningagent was immersed in a mixture containing a 10 wt. % aqueous sulfuricacid solution (5.6 kg) and a 30 wt. % aqueous hydrogen peroxide solution(0.2 kg). Insoluble components were removed from the mixture solutionthrough filtration, and a 15 wt. % aqueous solution (4 kg) of sodiumcarbonate serving as a precipitant for copper and manganese was added tothe filtrate, to thereby cause a copper component and a manganesecomponent to precipitate. The obtained precipitate was filtered, washedwith water, and kneaded with aluminum oxide (24 g) by means of akneader. The resultant mixture was dried at 120° C., to thereby recoverthe copper component and the manganese component in the form of cupricoxide and manganese dioxide, respectively. The thus-recovered matter wasfound to comprise cupric oxide (25 wt. %), manganese dioxide (69 wt. %),and aluminum oxide (6 wt. %). The recovered matter was further formedinto pellets (diameter: 6 mm, height: 6 mm). The pellets were milled,and, after having passed 12-mesh to 28-mesh sieves, the product wasemployed as a cleaning agent G′. The BET specific surface area of thecleaning agent G′ was found to be 172 m²/g.

[0135] Cleaning Harmful Gas Containing Silane by Use of RegeneratedCleaning Agent

[0136] In a manner similar to that employed in the cleaning of a harmfulgas by means of the cleaning agent G, the cleaning agent G′ was chargedinto a cleaning column (inside diameter: 40 mm) made of hard glass suchthat the pack length was adjusted to 100 mm. Into this cleaning column,a dry-nitrogen-based gas containing silane (10,000 ppm) as a harmfulcomponent was caused to pass at a flow rate of 2,000 ml/min (superficialvelocity: 2.65 cm/sec) at a temperature of 20° C. under atmosphericpressure, to thereby perform a cleaning test. The measurement results interms of cleaning performance of the cleaning agent G′ are shown inTable 1.

EXAMPLE 8

[0137] Preparation of Cleaning Agent Containing Copper Oxide andManganese Oxide

[0138] Commercial copper sulfate pentahydrate (0.5 kg) and manganesesulfate heptahydrate (1.41 kg) were dissolved in ion-exchange water (5L). To the resultant solution, a 15 wt. % aqueous solution (4.3 kg) ofsodium carbonate was added, to thereby cause a copper component and amanganese component to precipitate. The resultant precipitate wasfiltered, washed with water, and kneaded with potassium hydroxide (46 g)and silver oxide (13 g) by means of a kneader. The resultant mixture wasdried at 120° C., to thereby prepare a cleaning agent raw materialcomprising cupric oxide (24 wt. %), manganese dioxide (67 wt. %),potassium hydroxide (7 wt. %), and silver oxide (2 wt. %). Thethus-prepared raw material was formed into pellets (diameter: 6 mm,height: 6 mm). The pellets were milled, and, after having passed 12-meshto 28-mesh sieves, the product was employed as a cleaning agent H. TheBET specific surface area of the cleaning agent H was found to be 142m²/g.

[0139] Cleaning Harmful Gas Containing Disilane

[0140] The procedure of Example 7 was repeated, except that a gascontaining disilane (10,000 ppm) was used instead of a gas containingsilane (10,000 ppm) and that the cleaning agent H was used instead ofthe cleaning agent G employed in “Cleaning Harmful Gas ContainingSilane” of Example 7, to thereby clean a harmful gas containingdisilane. The measurement results in terms of cleaning performance ofthe cleaning agent H are shown in Table 1.

[0141] Recovery of Copper Component and Manganese Component fromCleaning Agent

[0142] The cleaning agent H, having been used in a manner similar tothat employed in the aforementioned cleaning of a harmful gas containingdisilane, was collected in an amount of 500 g, and the collectedcleaning agent was immersed in a mixture containing a 10 wt. % aqueousnitric acid solution (7.2 kg) and a 30 wt. % aqueous hydrogen peroxidesolution (0.2 kg). Insoluble components were removed from the mixturesolution through filtration, and a 15 wt. % aqueous solution (4 kg) ofsodium carbonate serving as a precipitant for copper and manganese wasadded to the filtrate, to thereby cause a copper component and amanganese component to precipitate. The obtained precipitate wasfiltered, washed with water, and kneaded with potassium hydroxide (28 g)by means of a kneader. The resultant mixture was dried at 120° C., tothereby recover the copper component and the manganese component in theform of cupric oxide and manganese dioxide, respectively. Thethus-recovered matter was found to comprise cupric oxide (24 wt. %),manganese dioxide (67 wt. %), potassium hydroxide (7 wt. %), and silveroxide (2 wt. %). The recovered matter was further formed into pellets(diameter: 6 mm, height: 6 mm). The pellets were milled, and, afterhaving passed 12-mesh to 28-mesh sieves, the milled product was employedas a cleaning agent H′. The BET specific surface area of the cleaningagent H′ was found to be 145 m²/g

[0143] Cleaning Harmful Gas Containing Disilane by Use of RegeneratedCleaning Agent

[0144] The procedure of Example 7 was repeated, except that a gascontaining disilane (10,000 ppm) was used instead of a gas containingsilane (10,000 ppm) and that the cleaning agent H′ was used instead ofthe cleaning agent G′ employed in “Cleaning Harmful Gas ContainingSilane by Use of Regenerated Cleaning Agent” of Example 7, to therebyperform a cleaning test for a harmful gas containing disilane. Themeasurement results in terms of cleaning performance of the cleaningagent H′ are shown in Table 1.

Example 9

[0145] Preparation of Cleaning Agent Containing Copper Oxide andManganese Oxide

[0146] Commercial copper sulfate pentahydrate (0.5 kg) and manganesesulfate heptahydrate (1.47 kg) were dissolved in ion-exchange water (5L). To the resultant solution, a 15 wt. % aqueous solution (4.3 kg) ofsodium carbonate was added, to thereby cause a copper component and amanganese component to precipitate. The resultant precipitate wasfiltered, washed with water, and kneaded with potassium hydroxide (48 g)and cobalt oxide (21 g) by means of a kneader. The resultant mixture wasdried at 120° C., to thereby prepare a cleaning agent raw materialcomprising cupric oxide (23 wt. %), manganese dioxide (67 wt. %),potassium hydroxide (7 wt. %), and cobalt oxide (3 wt. %). Thethus-prepared raw material was formed into pellets (diameter: 6 mm,height: 6 mm). The pellets were milled, and, after having passed 12-meshto 28-mesh sieves, the product was employed as a cleaning agent I. TheBET specific surface area of the cleaning agent I was found to be 163m²/g.

[0147] Cleaning Harmful Gas Containing Dichlorosilane

[0148] The procedure of Example 7 was repeated, except that a gascontaining dichlorosilane (10,000 ppm) was used instead of a gascontaining silane (10,000 ppm) and that the cleaning agent I was usedinstead of the cleaning agent G employed in “Cleaning Harmful GasContaining Silane” of Example 7, to thereby clean a harmful gascontaining dichlorosilane. The measurement results in terms of cleaningperformance of the cleaning agent I are shown in Table 1.

[0149] Recovery of Copper Component and Manganese Component fromCleaning Agent

[0150] The cleaning agent I, having been used in a manner similar tothat employed in the aforementioned cleaning of a harmful gas containingdichlorosilane, was collected in an amount of 500 g, and the collectedcleaning agent was immersed in a mixture containing a 10 wt. % aqueoussulfuric acid solution (5.6 kg) and a 30 wt. % aqueous hydrogen peroxidesolution (0.2 kg). Insoluble components were removed from the mixturesolution through filtration, and a 15 wt. % aqueous solution (4 kg) ofsodium carbonate serving as a precipitant for copper and manganese wasadded to the filtrate, to thereby cause a copper component and amanganese component to precipitate. The obtained precipitate wasfiltered, washed with water, and kneaded with potassium hydroxide (28 g)by means of a kneader. The resultant mixture was dried at 120° C., tothereby recover the copper component and the manganese component in theform of cupric oxide and manganese dioxide, respectively. Thethus-recovered matter was found to comprise cupric oxide (23 wt. %),manganese dioxide (67 wt. %), potassium hydroxide (7 wt. %), and cobaltoxide (3 wt. %). The recovered matter was further formed into pellets(diameter: 6 mm, height: 6 mm). The pellets were milled, and, afterhaving passed 12-mesh to 28-mesh sieves, the product was employed as acleaning agent I′. The BET specific surface area of the cleaning agentI′ was found to be 145 m²/g.

[0151] Cleaning Harmful Gas Containing Dichlorosilane by Use ofRegenerated Cleaning Agent

[0152] The procedure of Example 7 was repeated, except that a gascontaining dichlorosilane (10,000 ppm) was used instead of a gascontaining silane (10,000 ppm) and that the cleaning agent I′ was usedinstead of the cleaning agent G′ employed in “Cleaning Harmful GasContaining Silane by Use of Regenerated Cleaning Agent ” of Example 7,to thereby perform a cleaning test for a harmful gas containingdichlorosilane. The measurement results in terms of cleaning performanceof the cleaning agent I′ are shown in Table 1. TABLE 1 Cleaning agentcomponents Precipitant Cleaning Cleaning Harmful predominant/Precipitant for Cu and performance performance component additive for Por Si Mn (frist use) (regenerated) Ex. 1 phosphine CuO/Al₂O₃ — Na₂CO₃116 110 Ex. 2 phosphine CuO/ZrO₂ — Na₂CO₃ 112 118 Ex. 3 t-butyl CuO/ZnO— NaOH 16 17 phosphine Ex. 4 phosphine CuO/SiO₂ MgSO₄ Na₂CO₃ 118 125 Ex.5 phosphine CuO, MnO₂/Al₂O₃ — Na₂CO₃ 40 42 Ex. 6 phosphine CuO,MnO₂/Al₂O₃ MgSO₄ Na₂CO₃ 43 40 Ex. 7 silane CuO, MnO₂/Al₂O₃ — Na₂CO₃ 2120 Ex. 8 disilane CuO, MnO₂/KOH, Ag₂O — Na₂CO₃ 15 16 Ex. 9dichloro-silane CuO, MnO₂/KOH, CoO — Na₂CO₃ 45 44

EXAMPLE 10

[0153] Preparation of Cleaning Agent Containing Basic Copper Carbonate

[0154] Commercial copper sulfate pentahydrate (1.5 kg) was dissolved inion-exchange water (5 L). To the resultant solution, a 15 wt. % aqueoussolution (4.3 kg) of sodium carbonate was added, to thereby cause acopper component to precipitate. The resultant precipitate was filtered,washed with water, and dried at 120° C., to thereby prepare basic coppercarbonate. The thus-prepared basic copper carbonate was formed intopellets (diameter: 6 mm, height: 6 mm). The pellets were milled, and,after having passed 12-mesh to 28-mesh sieves, the milled product wasemployed as a cleaning agent a. The BET specific surface area of basiccopper carbonate (cleaning agent a), as measured by means of a gasadsorption amount measurement apparatus (Autosorb 3B, product of YuasaIonics), was 66 m²/g.

[0155] Cleaning Harmful Gas Containing Phosphine

[0156] The cleaning agent a was charged into a cleaning column (insidediameter: 40 mm) made of hard glass such that the pack length wasadjusted to 100 mm. Into this cleaning column, a dry-nitrogen-based gascontaining phosphine (10,000 ppm) as a harmful component was caused topass at 20° C. under atmospheric pressure at a flow rate of 2,000 ml/min(superficial velocity: 2.65 cm/sec). During passage of the gas, aportion of the gas flown from the outlet of the cleaning column wasaspirated into a detection tube (Phosphine 7L, product of Gastech,detection limit: 0.15 ppm), and the time elapsed until detection ofphosphine (effective treatment time) was measured, to thereby obtain theamount (L) of phosphine removed per liter (L) of a cleaning agent(cleaning performance). The results are shown in Table 2.

[0157] Recovery of Copper Component from Cleaning Agent

[0158] The cleaning agent a, having been used in a manner similar tothat employed in the aforementioned “Cleaning Harmful Gas ContainingPhosphine,” was collected in an amount of 500 g, and the collectedcleaning agent was immersed in a 10 wt. % aqueous sulfuric acid solution(6.0 kg) for dissolution. Insoluble components were removed from theacid solution through filtration, and a 15 wt. % aqueous solution (4.3kg) of sodium carbonate serving as a precipitant for copper was added tothe filtrate, to thereby cause a copper component to precipitate. Theresultant precipitate was filtered, washed with water, and dried at 120°C., to thereby recover the copper component in the form of basic coppercarbonate. The thus-recovered basic copper carbonate was further formedinto pellets (diameter: 6 mm, height: 6 mm). The pellets were milled,and, after having passed 12-mesh to 28-mesh sieves, the milled productwas employed as a cleaning agent b. The BET specific surface area of therecovered basic copper carbonate (cleaning agent b) was found to be 64m²/g.

[0159] Cleaning Harmful Gas Containing Phosphine by Use of RegeneratedCleaning Agent

[0160] In a manner similar to that employed in the aforementioned“Cleaning Harmful Gas Containing Phosphine,” the cleaning agent b wascharged into a cleaning column (inside diameter: 40 mm) made of hardglass such that the pack length was adjusted to 100 mm. Into thiscleaning column, a dry-nitrogen-based gas containing phosphine (10,000ppm) as a harmful component was caused to pass at 20° C. underatmospheric pressure at a flow rate of 2,000 ml/min (superficialvelocity: 2.65 cm/sec), to thereby perform a cleaning test. Themeasurement results in terms of cleaning performance of the cleaningagent b are shown in Table 2.

EXAMPLE 11 Recovery of Copper Component from Cleaning Agent

[0161] The cleaning agent a, having been used in a manner similar tothat employed in the “Cleaning Harmful Gas Containing Phosphine” ofExample 10, was collected in an amount of 500 g, and the collectedcleaning agent was immersed in a 10 wt. % aqueous sulfuric acid solution(6.0 kg) for dissolution. Insoluble components were removed from theacid solution through filtration, and a 4.1 wt. % aqueous solution (6.0kg) of sodium hydroxide serving as a precipitant for copper was added tothe filtrate, to thereby cause a copper component to precipitate. Theresultant precipitate was filtered, washed with water, and dried at 120°C., to thereby recover the copper component in the form of copperhydroxide. The thus-recovered copper hydroxide was further formed intopellets (diameter: 6 mm, height: 6 mm). The pellets were milled, and,after having passed 12-mesh to 28-mesh sieves, the product was employedas a cleaning agent c. The BET specific surface area of the recoveredcopper hydroxide (cleaning agent c) was found to be 40 m²/g.

[0162] Cleaning Harmful Gas Containing Phosphine by Use of RegeneratedCleaning Agent

[0163] In a manner similar to that employed in the “Cleaning Harmful GasContaining Phosphine by Use of Regenerated Cleaning Agent” of Example10, the cleaning agent c was charged into a cleaning column (insidediameter: 40 mm) made of hard glass such that the pack length wasadjusted to 100 mm. Into this cleaning column, a dry-nitrogen-based gascontaining phosphine (10,000 ppm) as a harmful component was caused topass at 20° C. under atmospheric pressure at a flow rate of 2,000 ml/min(superficial velocity: 2.65 cm/sec), to thereby perform a cleaning test.The measurement results in terms of cleaning performance of the cleaningagent c are shown in Table 2.

Example 12

[0164] Recovery of Copper Component from Cleaning Agent

[0165] The cleaning agent a, having been used in a manner similar tothat employed in the “Cleaning Harmful Gas Containing Phosphine” ofExample 10, was collected in an amount of 500 g, and the collectedcleaning agent was immersed in a 10 wt. % aqueous sulfuric acid solution(6.0 kg) for dissolution. Insoluble components were removed from theacid solution through filtration, and a 15 wt. % aqueous solution (4.3kg) of sodium carbonate serving as a precipitant for copper was added tothe filtrate, to thereby cause a copper component to precipitate. Theresultant precipitate was filtered, washed with water, and kneaded withaluminum oxide (16 g) by means of a kneader. The resultant mixture wasdried at 120° C. and calcined at 350° C., to thereby recover the coppercomponent in the form of cupric oxide. The thus-recovered matter wasfound to comprise cupric oxide (96 wt. %) and aluminum oxide (4 wt. %).The recovered matter was further formed into pellets (diameter: 6 mm,height: 6 mm). The pellets were milled, and, after having passed 12-meshto 28-mesh sieves, the product was employed as a cleaning agent d. TheBET specific surface area of the cleaning agent d was found to be 83m²/g.

[0166] Cleaning Harmful Gas Containing Phosphine by Use of RegeneratedCleaning Agent

[0167] In a manner similar to that employed in the “Cleaning Harmful GasContaining Phosphine by Use of Regenerated Cleaning Agent” of Example10, the cleaning agent d was charged into a cleaning column (insidediameter: 40 mm) made of hard glass such that the pack length wasadjusted to 100 mm. Into this cleaning column, a dry-nitrogen-based gascontaining phosphine (10,000 ppm) as a harmful component was caused topass at 20° C. under atmospheric pressure at a flow rate of 2,000 ml/min(superficial velocity: 2.65 cm/sec), to thereby perform a cleaning test.The measurement results in terms of cleaning performance of the cleaningagent d are shown in Table 2.

Example 13

[0168] Cleaning Harmful Gas Containing t-Butylphosphine

[0169] The cleaning agent a which had been prepared in a manner similarto that of Example 10 was charged into a cleaning column (insidediameter: 40 mm) made of hard glass such that the pack length wasadjusted to 100 mm. Into this cleaning column, a dry-nitrogen-based gascontaining t-butylphosphine (10,000 ppm) as a harmful component wascaused to pass at a flow rate of 2,000 ml/min (superficial velocity:2.65 cm/sec) at a temperature of 20° C. under atmospheric pressure.During passage of the gas, a portion of the gas flown from the outlet ofthe cleaning column was aspirated into a detection tube (Phosphine 7 L,product of Gastech, detection limit: 0.15 ppm), and the time elapseduntil detection of t-butylphosphine (effective treatment time) wasmeasured, to thereby obtain the amount (L) of t-butylphosphine removedper liter (L) of a cleaning agent (cleaning performance). The resultsare shown in Table 2.

[0170] Recovery of Copper Component from Cleaning Agent

[0171] The cleaning agent a, having been used in a manner similar tothat employed in the aforementioned “Cleaning Harmful Gas Containingt-Butylphosphine” was collected in an amount of 500 g, and the collectedcleaning agent was immersed in a 10 wt. % aqueous sulfuric acid solution(6.0 kg) for dissolution. Insoluble components were removed from theacid solution through filtration, and a 15 wt. % aqueous solution (4.3kg) of sodium carbonate serving as a precipitant for copper was added tothe filtrate, to thereby cause a copper component to precipitate. Theresultant precipitate was filtered, washed with water, and dried at 120°C., to thereby recover the copper component in the form of basic coppercarbonate. The thus-recovered basic copper carbonate was further formedinto pellets (diameter: 6 mm, height: 6 mm). The pellets were milled,and, after having passed 12-mesh to 28-mesh sieves, the milled productwas employed as a cleaning agent e. The BET specific surface area of therecovered basic copper carbonate (cleaning agent e) was found to be 62m²/g.

[0172] Cleaning Harmful Gas Containing t-Butylohosphine by Use ofRegenerated Cleaning Agent

[0173] In a manner similar to that employed in the aforementioned“Cleaning Harmful Gas Containing t-Butylphosphine” the cleaning agent ewas charged into a cleaning column (inside diameter: 40 mm) made of hardglass such that the pack length was adjusted to 100 mm. Into thiscleaning column, a dry-nitrogen-based gas containing t-butylphosphine(10,000 ppm) as a harmful component was caused to pass at a flow rate of2,000 ml/min (superficial velocity: 2.65 cm/sec) at a temperature of 20°C. under atmospheric pressure, to thereby perform a cleaning test. Themeasurement results in terms of cleaning performance of the cleaningagent e are shown in Table 2.

Example 14

[0174] Recovery of Copper Component from Cleaning Agent

[0175] The cleaning agent a, having been used in a manner similar tothat employed in the “Cleaning Harmful Gas Containing Phosphine” ofExample 10, was collected in an amount of 500 g, and the collectedcleaning agent was immersed in a 10 wt. % aqueous sulfuric acid solution(6.0 kg) for dissolution. Subsequently, a 15 wt. % aqueous solution (1.5kg) of magnesium sulfate serving as a precipitant for phosphorus wasadded to the resultant solution, to thereby cause a phosphorus componentto precipitate. The resultant precipitate was removed throughfiltration, and a 15 wt. % aqueous solution (4.3 kg) of sodium carbonateserving as a precipitant for copper was added to the filtrate, tothereby cause a copper component to precipitate. The resultantprecipitate was filtered, washed with water, and dried at 120° C., tothereby recover the copper component in the form of basic coppercarbonate. The thus-recovered basic copper carbonate was further formedinto pellets (diameter: 6 mm, height: 6 mm). The pellets were milled,and, after having passed 12-mesh to 28-mesh sieves, the milled productwas employed as a cleaning agent f. The BET specific surface area of therecovered basic copper carbonate (cleaning agent f) was found to be 64m²/mg.

[0176] Cleaning Harmful Gas Containing Phosphine by Use of RegeneratedCleaning Agent

[0177] In a manner similar to that employed in the “Cleaning Harmful GasContaining Phosphine by Use of Regenerated Cleaning Agent” of Example10, the cleaning agent f was charged into a cleaning column (insidediameter: 40 mm) made of hard glass such that the pack length wasadjusted to 100 mm. Into this cleaning column, a dry-nitrogen-based gascontaining phosphine (10,000 ppm) as a harmful component was caused topass at a flow rate of 2,000 ml/min (superficial velocity: 2.65 cm/sec)at a temperature of 20° C. under atmospheric pressure, to therebyperform a cleaning test. The measurement results in terms of cleaningperformance of the cleaning agent f are shown in Table 2.

Example 15

[0178] Preparation of Cleaning Agent Containing Copper Hydroxide

[0179] Commercial copper sulfate pentahydrate (1.5 kg) was dissolved inion-exchange water (5 L). To the resultant solution, a 16 wt. % aqueoussolution (1.5 kg) of sodium hydroxide was added, to thereby cause acopper component to precipitate. The resultant precipitate was filtered,washed with water, and dried at 120° C., to thereby prepare copperhydroxide. The thus-prepared copper hydroxide was formed into pellets(diameter: 6 mm, height: 6 mm). The pellets were milled, and, afterhaving passed 12-mesh to 28-mesh sieves, the product was employed as acleaning agent g. The BET specific surface area of copper hydroxide(cleaning agent g), as measured by means of a gas adsorption amountmeasurement apparatus, was 41 m²/g.

[0180] Cleaning Harmful Gas Containing Phosphine

[0181] The cleaning agent g was charged into a cleaning column (insidediameter: 40 mm) made of hard glass such that the pack length wasadjusted to 100 mm. Into this cleaning column, a dry-nitrogen-based gascontaining phosphine (10,000 ppm) as a harmful component was caused topass at 20° C. under atmospheric pressure at a flow rate of 2,000 ml/min(superficial velocity: 2.65 cm/sec). During passage of the gas, aportion of the gas flown from the outlet of the cleaning column wasaspirated into a detection tube (Phosphine 7 L, product of Gastech,detection limit: 0.15 ppm), and the time elapsed until detection ofphosphine (effective treatment time) was measured, to thereby obtain theamount (L) of phosphine removed per liter (L) of a cleaning agent(cleaning performance). The results are shown in Table 2.

[0182] Recovery of Copper Component from Cleaning Agent

[0183] The cleaning agent g, having been used in a manner similar tothat employed in the aforementioned “Cleaning Harmful Gas ContainingPhosphine,” was collected in an amount of 500 g, and the collectedcleaning agent was immersed in a 10 wt. % aqueous sulfuric acid solution(6.0 kg) for dissolution. Insoluble components were removed from theacid solution through filtration, and a 4.1 wt. % aqueous solution (6.0kg) of sodium hydroxide serving as a precipitant for copper was added tothe filtrate, to thereby cause a copper component to precipitate. Theresultant precipitate was filtered, washed with water, and dried at 120°C., to thereby recover the copper component in the form of copperhydroxide. The thus-recovered copper hydroxide was further formed intopellets (diameter: 6 mm, height: 6 mm). The pellets were milled, and,after having passed 12-mesh to 28-mesh sieves, the milled product wasemployed as a cleaning agent h. The BET specific surface area of therecovered copper hydroxide (cleaning agent h) was found to be 42 m²/g.

[0184] Cleaning Harmful Gas Containing Phosphine by Use of RegeneratedCleaning Agent

[0185] In a manner similar to that employed in the aforementioned“Cleaning Harmful Gas Containing Phosphine,” the cleaning agent h wascharged into a cleaning column (inside diameter: 40 mm) made of hardglass such that the pack length was adjusted to 100 mm. Into thiscleaning column, a dry-nitrogen-based gas containing phosphine (10,000ppm) as a harmful component was caused to pass at a flow rate of 2,000ml/min (superficial velocity: 2.65 cm/sec) at a temperature of 20° C.under atmospheric pressure, to thereby perform a cleaning test. Themeasurement results in terms of cleaning performance of the cleaningagent h are shown in Table 2.

Example 16

[0186] Recovery of Cooler Component from Cleaning Agent

[0187] The cleaning agent g, having been used in a manner similar tothat employed in the “Cleaning Harmful Gas Containing Phosphine” ofExample 15, was collected in an amount of 500 g, and the collectedcleaning agent was immersed in a 10 wt. % aqueous sulfuric acid solution(6.0 kg) for dissolution. Subsequently, a 15 wt. % aqueous solution (1.5kg) of magnesium sulfate serving as a precipitant for phosphorus wasadded to the resultant solution, to thereby cause a phosphorus componentto precipitate. The resultant precipitate was removed from the acidsolution through filtration, and a 5.3 wt. % aqueous solution (6.0 kg)of sodium hydroxide serving as a precipitant for copper was added to thefiltrate, to thereby cause a copper component to precipitate. Theresultant precipitate was filtered, washed with water, and dried at 120°C., to thereby recover the copper component in the form of copperhydroxide. The thus-recovered copper hydroxide was further formed intopellets (diameter: 6 mm, height: 6 mm). The pellets were milled, and,after having passed 12-mesh to 28-mesh sieves, the product was employedas a cleaning agent i. The BET specific surface area of the recoveredcopper hydroxide (cleaning agent i) was found to be 38 m²/g.

[0188] Cleaning Harmful Gas Containing Phosphine by Use of RegeneratedCleaning Agent

[0189] In a manner similar to that employed in the “Cleaning Harmful GasContaining Phosphine by Use of Regenerated Cleaning Agent” of Example15, the cleaning agent i was charged into a cleaning column (insidediameter: 40 mm) made of hard glass such that the pack length wasadjusted to 100 mm. Into this cleaning column, a dry-nitrogen-based gascontaining phosphine (10,000 ppm) as a harmful component was caused topass at 20° C. under atmospheric pressure at a flow rate of 2,000 ml/min(superficial velocity: 2.65 cm/sec), to thereby perform a cleaning test.The measurement results in terms of cleaning performance of the cleaningagent i are shown in Table 2.

EXAMPLE 17

[0190] Cleaning Harmful Gas Containing Silane

[0191] The cleaning agent a which had been prepared in a manner similarto that of Example 10 was charged into a cleaning column (insidediameter: 40 mm) made of hard glass such that the pack length wasadjusted to 100 mm. Into this cleaning column, a dry-nitrogen-based gascontaining silane (10,000 ppm) as a harmful component was caused to passat a flow rate of 2,000 ml/min (superficial velocity: 2.65 cm/sec) at atemperature of 20° C. under atmospheric pressure. During passage of thegas, a portion of the gas flown from the outlet of the cleaning columnwas aspirated into a detection tube (Silane S, product of Komyo RikagakuKogyo, detection limit: 0.5 ppm), and the time elapsed until detectionof silane (effective treatment time) was measured, to thereby obtain theamount (L) of silane removed per liter (L) of a cleaning agent (cleaningperformance). The results are shown in Table 2.

[0192] Recovery of Copper Component from Cleaning Agent

[0193] The cleaning agent a, having been used in a manner similar tothat employed in the aforementioned “Cleaning Harmful Gas ContainingSilane,” was collected in an amount of 500 g, and the collected cleaningagent was immersed in a mixture containing a 10 wt. % aqueous sulfuricacid solution (5.6 kg) and a 30 wt. % aqueous hydrogen peroxide solution(0.2 kg). Insoluble components were removed from the mixture solutionthrough filtration, and a 15 wt. % aqueous solution (4.3 kg) of sodiumcarbonate serving as a precipitant for copper was added to the filtrate,to thereby cause a copper component to precipitate. The obtainedprecipitate was filtered, washed with water, dried at 120° C., tothereby recover the copper component in the form of basic coppercarbonate. The thus-recovered basic copper carbonate was further formedinto pellets (diameter: 6 mm, height: 6 mm). The pellets were milled,and, after having passed 12-mesh to 28-mesh sieves, the product wasemployed as a cleaning agent j. The BET specific surface area of therecovered basic copper carbonate (cleaning agent j) was found to be 61m²/g.

[0194] Cleaning Harmful Gas Containing Silane by Use of RegeneratedCleaning Agent

[0195] In a manner similar to that employed in the aforementioned“Cleaning Harmful Gas Containing Silane,” the cleaning agent j wascharged into a cleaning column (inside diameter: 40 mm) made of hardglass such that the pack length was adjusted to 100 mm. Into thiscleaning column, a dry-nitrogen-based gas containing silane (10,000 ppm)as a harmful component was caused to pass at a flow rate of 2,000 ml/min(superficial velocity: 2.65 cm/sec) at a temperature of 20° C. underatmospheric pressure, to thereby perform a cleaning test. Themeasurement results in terms of cleaning performance of the cleaningagent j are shown in Table 2.

Example 18

[0196] Recovery of Copper Component from Cleaning Agent

[0197] The cleaning agent a, having been used in a manner similar tothat employed in the “Cleaning Harmful Gas Containing Silane” of Example17, was collected in an amount of 500 g, and the collected cleaningagent was immersed in a mixture containing a 10 wt. % aqueous sulfuricacid solution (5.6 kg) and a 30 wt. % aqueous hydrogen peroxide solution(0.2 kg). Insoluble components were removed from the mixture solutionthrough filtration, and a 4.1 wt. % aqueous solution (6.0 kg) of sodiumhydroxide serving as a precipitant for copper was added to the filtrate,to thereby cause a copper component to precipitate. The obtainedprecipitate was filtered, washed with water, dried at 120° C., tothereby recover the copper component in the form of copper hydroxide.The thus-recovered copper hydroxide was further formed into pellets(diameter: 6 mm, height: 6 mm). The pellets were milled, and, afterhaving passed 12-mesh to 28-mesh sieves, the milled product was employedas a cleaning agent k. The BET specific surface area of the recoveredcopper hydroxide (cleaning agent k) was found to be 39 m²/g.

[0198] Cleaning Harmful Gas Containing Silane by Use of RegeneratedCleaning Agent

[0199] In a manner similar to that employed in the “Cleaning Harmful GasContaining Silane by Use of Regenerated Cleaning agent” of Example 17,the cleaning agent k was charged into a cleaning column (insidediameter: 40 mm) made of hard glass such that the pack length wasadjusted to 100 mm. Into this cleaning column, a dry-nitrogen-based gascontaining silane (10,000 ppm) as a harmful component was caused to passat 20° C. under atmospheric pressure at a flow rate of 2,000 ml/min(superficial velocity: 2.65 cm/sec), to thereby perform a cleaning test.The measurement results in terms of cleaning performance of the cleaningagent k are shown in Table 2.

Example 19

[0200] Recovery of Copper Component from Cleaning Agent

[0201] The cleaning agent a, having been used in a manner similar tothat employed in the “Cleaning Harmful Gas Containing Silane” of Example17, was collected in an amount of 500 g, and the collected cleaningagent was immersed in a mixture containing a 10 wt. % aqueous sulfuricacid solution (5.6 kg) and a 30 wt. % aqueous hydrogen peroxide solution(0.2 kg). Insoluble components were removed from the mixture solutionthrough filtration, and a 15 wt. % aqueous solution (4.3 kg) of sodiumcarbonate serving as a precipitant for copper was added to the filtrate,to thereby cause a copper component to precipitate. The resultantprecipitate was filtered, washed with water, and kneaded with aluminumoxide (16 g) by means of a kneader. The resultant mixture was dried at120° C. and calcined at 350° C., to thereby recover the copper componentin the form of cupric oxide. The thus-recovered matter was found tocomprise cupric oxide (96 wt. %) and aluminum oxide (4 wt. %). Therecovered matter was further formed into pellets (diameter: 6 mm,height: 6 mm). The pellets were milled, and, after having passed 12-meshto 28-mesh sieves, the milled product was employed as a cleaning agentl. The BET specific surface area of the cleaning agent 1 was found to be81 m²/g.

[0202] Cleaning Harmful Gas Containing Silane by Use of RegeneratedCleaning Agent

[0203] In a manner similar to that employed in the “Cleaning Harmful GasContaining Silane by Use of Regenerated Cleaning Agent” of Example 17,the cleaning agent 1 was charged into a cleaning column (insidediameter: 40 mm) made of hard glass such that the pack length wasadjusted to 100 mm. Into this cleaning column, a dry-nitrogen-based gascontaining silane (10,000 ppm) as a harmful component was caused to passat a flow rate of 2,000 ml/min (superficial velocity: 2.65 cm/sec) at atemperature of 20° C. under atmospheric pressure, to thereby perform acleaning test. The measurement results in terms of cleaning performanceof the cleaning agent 1 are shown in Table 2.

Example 20

[0204] Cleaning Harmful Gas Containing Disilane

[0205] The cleaning agent a which had been prepared in a manner similarto that of Example 10 was charged into a cleaning column (insidediameter: 40 mm) made of hard glass such that the pack length wasadjusted to 100 mm. Into this cleaning column, a dry-nitrogen-based gascontaining disilane (10,000 ppm) as a harmful component was caused topass at a flow rate of 2,000 ml/min (superficial velocity: 2.65 cm/sec)at a temperature of 20° C. under atmospheric pressure. During passage ofthe gas, a portion of the gas flown from the outlet of the cleaningcolumn was aspirated into a detection tube (Silane S, product of KomyoRikagaku Kogyo, detection limit: 0.5 ppm), and the time elapsed untildetection of disilane (effective treatment time) was measured, tothereby obtain the amount (L) of disilane removed per liter (L) of acleaning agent (cleaning performance). The results are shown in Table 2.

[0206] Recovery of Copper Component from Cleaning Agent

[0207] The cleaning agent a, having been used in a manner similar tothat employed in the aforementioned “Cleaning Harmful Gas ContainingDisilane,” was collected in an amount of 500 g, and the collectedcleaning agent was immersed in a mixture containing a 10 wt. % aqueoussulfuric acid solution (5.6 kg) and a 30 wt. % aqueous hydrogen peroxidesolution (0.2 kg). Insoluble components were removed from the mixturesolution through filtration, and a 15 wt. % aqueous solution (4.3 kg) ofsodium carbonate serving as a precipitant for copper was added to thefiltrate, to thereby cause a copper component to precipitate. Theobtained precipitate was filtered, washed with water, dried at 120° C.,to thereby recover the copper component in the form of basic coppercarbonate. The thus-recovered basic copper carbonate was further formedinto pellets (diameter: 6 mm, height: 6 mm). The pellets were milled,and and, after having passed 12-mesh to 28-mesh sieves, the product wasemployed as a cleaning agent m. The BET specific surface area of therecovered basic copper carbonate (cleaning agent m) was found to be 63m²/g.

[0208] Cleaning Harmful Gas Containing Diilane by Use of RegeneratedCleaning Agent

[0209] In a manner similar to that employed in the aforementioned“Cleaning Harmful Gas Containing Disilane,” the cleaning agent m wascharged into a cleaning column (inside diameter: 40 mm) made of hardglass such that the pack length was adjusted to 100 mm. Into thiscleaning column, a dry-nitrogen-based gas containing disilane (10,000ppm) as a harmful component was caused to pass at a flow rate of 2,000ml/min (superficial velocity: 2.65 cm/sec) at a temperature of 20° C.under atmospheric pressure, to thereby perform a cleaning test. Themeasurement results in terms of cleaning performance of the cleaningagent m are shown in Table 2.

Example 21

[0210] Cleaning Harmful Gas Containing Dichlorosilane

[0211] The cleaning agent g which had been prepared in a manner similarto that of Example 15 was charged into a cleaning column (insidediameter: 40 mm) made of hard glass such that the pack length wasadjusted to 100 mm. Into this cleaning column, a dry-nitrogen-based gascontaining dichlorosilane (10,000 ppm) as a harmful component was causedto pass at a flow rate of 2,000 ml/min (superficial velocity: 2.65cm/sec) at a temperature of 20° C. under atmospheric pressure. Duringpassage of the gas, a portion of the gas flown from the outlet of thecleaning column was aspirated into a detection tube (product of Gastech,detection limit: 0.05 ppm), and the time elapsed until detection ofdichlorosilane (effective treatment time) was measured, to therebyobtain the amount (L) of dichlorosilane removed per liter (L) of acleaning agent (cleaning performance). The results are shown in Table 2.

[0212] Recovery of Copper Component from Cleaning Agent

[0213] The cleaning agent g, having been used in a manner similar tothat employed in the aforementioned “Cleaning Harmful Gas ContainingDichlorosilane,” was collected in an amount of 500 g, and the collectedcleaning agent was immersed in a mixture containing a 10 wt. % aqueoussulfuric acid solution (5.6 kg) and a 30 wt. % aqueous hydrogen peroxidesolution (0.2 kg). Insoluble components were removed from the mixturesolution through filtration, and a 4.1 wt. % aqueous solution (6.0 kg)of sodium hydroxide serving as a precipitant for copper was added to thefiltrate, to thereby cause a copper component to precipitate. Theobtained precipitate was filtered, washed with water, dried at 120° C.,to thereby recover the copper component in the form of copper hydroxide.The thus-recovered copper hydroxide was further formed into pellets(diameter: 6 mm, height: 6 mm). The pellets were milled, and, afterhaving passed 12-mesh to 28-mesh sieves, the product was employed as acleaning agent n. The BET specific surface area of the recovered copperhydroxide (cleaning agent n) was found to be 41 m²/g.

[0214] Cleaning Harmful Gas Containing Dichlorosilane by Use ofRegenerated Cleaning Agent

[0215] In a manner similar to that employed in the aforementioned“Cleaning Harmful Gas Containing Dichlorosilane,” the cleaning agent nwas charged into a cleaning column (inside diameter: 40 mm) made of hardglass such that the pack length was adjusted to 100 mm. Into thiscleaning column, a dry-nitrogen-based gas containing dichlorosilane(10,000 ppm) as a harmful component was caused to pass at 20° C. underatmospheric pressure at a flow rate of 2,000 ml/min (superficialvelocity: 2.65 cm/sec), to thereby perform a cleaning test. Themeasurement results in terms of cleaning performance of the cleaningagent n are shown in Table 2. TABLE 2-1 Cleaning agent Precipit-Recovered Cleaning Cleaning Harmful copper Precipit-ant ant cleaningagent performance performance component component for P for Cucomponents (first use) (regenerated) Ex. 10 phosphine basic copper —Na₂CO₃ basic copper 72 71 carbonate carbonate Ex. 11 phosphine basiccopper — NaOH copper hydroxide 72 65 carbonate Ex. 12 phosphine basiccopper — Na₂CO₃ copper oxide, 72 100 carbonate alumina Ex. 13 t-butyl-basic copper — Na₂CO₃ basic copper 11 11 phosphine carbonate carbonateEx. 14 phosphine basic copper MgSO₄ Na₂CO₃ basic copper 72 70 carbonatecarbonate Ex. 15 phosphine copper hydroxide — NaOH copper hydroxide 6665

[0216] TABLE 2-2 Cleaning agent Precipit- Recovered Cleaning CleaningHarmful copper Precipit-ant ant cleaning agent performance performancecomponent component for P for Cu components (first use) (regenerated)Ex. 16 phosphine copper hydroxide MgSO₄ NaOH copper hydroxide 66 66 Ex.17 silane basic copper — Na₂CO₃ basic copper 15 15 carbonate carbonateEx. 18 silane basic copper — NaOH copper hydroxide 15 12 carbonate Ex.19 silane basic copper — Na₂CO₃ copper oxide, 15 19 carbonate aluminaEx. 20 disilane basic copper — Na₂CO₃ basic copper 11 12 carbonatecarbonate Ex. 21 dichloro- copper hydroxide — NaOH copper hydroxide 3231 silane

[0217] As described hereinabove, a copper component can be recoveredfrom a cleaning agent which has been used for cleaning a harmful gascontaining as a harmful component a phosphine or a silane gas. Acleaning agent regenerated from the recovered copper component has beenconfirmed to exhibit cleaning performance as high as a fresh cleaningagent which has not been used for cleaning a harmful gas.

What is claimed is:
 1. A method of recovering a cleaning agent, thecleaning agent having been used for removing, through contact with aharmful gas, a phosphine contained as a harmful component in the harmfulgas, and being at least one species selected from among a cleaning agentcontaining copper oxide as a component thereof, a cleaning agentcontaining basic copper carbonate as a component thereof, and a cleaningagent containing copper hydroxide as a component thereof, the methodcomprising: immersing the cleaning agent in an acidic solution, tothereby dissolve the cleaning agent; adding to the resultant solution aprecipitant for copper, to thereby cause a copper compound toprecipitate; separating a copper component from a phosphorus componentwhich has been sorbed in the cleaning agent during the course ofcleaning the harmful gas; and recovering the copper component of thecleaning agent.
 2. A method of recovering a cleaning agent, the cleaningagent having been used for removing, through contact with a harmful gas,a phosphine contained as a harmful component in the harmful gas, andbeing at least one species selected from among a cleaning agentcontaining copper oxide as a component thereof, a cleaning agentcontaining basic copper carbonate as a component thereof, and a cleaningagent containing copper hydroxide as a component thereof, the methodcomprising: immersing the cleaning agent in an acidic solution, tothereby dissolve the cleaning agent; adding to the resultant solution aprecipitant for phosphorus, to thereby cause a phosphorus compound toprecipitate; separating a phosphorus component which has been sorbed inthe cleaning agent during the course of cleaning the harmful gas from acopper component; adding a precipitant for copper to the solution fromwhich the phosphorus component has been removed, to thereby cause acopper compound to precipitate; and recovering the copper component ofthe cleaning agent.
 3. A method of recovering a cleaning agent, thecleaning agent having been used for removing, through contact with aharmful gas, a silane gas contained as a harmful component in theharmful gas, and being at least one species selected from a cleaningagent containing basic copper carbonate as a component thereof and acleaning agent containing copper hydroxide as a component thereof, themethod comprising: immersing the cleaning agent in an acidic solution,to thereby transform a copper component to a soluble copper salt andcause a silicon component to precipitate in the form of silicon oxide,the silicon component having been sorbed in the cleaning agent duringthe course of cleaning the harmful gas; separating the silicon componentfrom the copper component; adding a precipitant for copper to thesolution from which the silicon component has been removed, to therebycause a copper compound to precipitate; and recovering the coppercomponent of the cleaning agent.
 4. A method of recovering a cleaningagent according to claim 1 or 2, wherein the cleaning agent containingcopper oxide as a component thereof further contains, before use of theagent, at least one species selected from a metal and a metal oxideother than copper oxide.
 5. A method of recovering a cleaning agentaccording to any one of claims 1 to 3, wherein, after formation ofprecipitates of the copper compound, the copper component contained inthe precipitates is recovered in the form of copper oxide, basic coppercarbonate, or copper hydroxide.
 6. A method of recovering a cleaningagent according to claim 5, wherein the copper oxide, basic coppercarbonate, or copper hydroxide which is to be recovered has a BETspecific surface area of 10 m²/g or more.
 7. A method of recovering acleaning agent according to any one of claims 1 to 3, wherein theprecipitant for copper is at least one species selected from amonglithium hydroxide, sodium hydroxide, potassium hydroxide, ammoniumhydroxide, sodium carbonate, potassium carbonate, ammonium carbonate,sodium hydrogencarbonate, potassium hydrogencarbonate, and ammoniumhydrogencarbonate.
 8. A method of recovering a cleaning agent accordingto any one of claims 1 to 3, wherein the cleaning agent containing basiccopper carbonate as a component thereof further contains, before use ofthe agent, at least one species selected from a metal and a metal oxide.9. A method of recovering a cleaning agent according to any one ofclaims 1 to 3, wherein the cleaning agent containing copper hydroxide asa component thereof further contains, before use of the agent, at leastone species selected from a metal and a metal oxide.
 10. A method ofrecovering a cleaning agent according to any one of claims 1 to 3,wherein the cleaning agent containing basic copper carbonate as acomponent thereof has, before use of the agent, a BET specific surfacearea of 10 m²/g or more.
 11. A method of recovering a cleaning agentaccording to any one of claims 1 to 3, wherein the cleaning agentcontaining copper hydroxide as a component thereof has, before use ofthe agent, a BET specific surface area of 10 m²/g or more.
 12. A methodof recovering a cleaning agent, the cleaning agent having been used forremoving, through contact with a harmful gas, a phosphine contained as aharmful component in the harmful gas, and containing copper oxide andmanganese oxide as components thereof, the method comprising: immersingthe cleaning agent in an acidic solution, to thereby dissolve thecleaning agent; adding to the resultant solution a precipitant forcopper and manganese, to thereby cause a copper compound and a manganesecompound to precipitate; separating a copper component and a manganesecomponent from a phosphorus component which has been sorbed in thecleaning agent during the course of cleaning the harmful gas; andrecovering the copper component and the manganese component of thecleaning agent.
 13. A method of recovering a cleaning agent, thecleaning agent having been used for removing, through contact with aharmful gas, a phosphine contained as a harmful component in the harmfulgas, and containing copper oxide and manganese oxide as componentsthereof, the method comprising: immersing the cleaning agent in anacidic solution, to thereby dissolve the cleaning agent; adding to theresultant solution a precipitant for phosphorus, to thereby cause aphosphorus compound to precipitate; separating a phosphorus componentwhich has been sorbed in the cleaning agent during the course ofcleaning the harmful gas from a copper component and a manganesecomponent; adding a precipitant for copper and manganese to the solutionfrom which the phosphorus component has been removed, to thereby cause acopper compound and a manganese compound to precipitate; and recoveringthe copper component and the manganese component of the cleaning agent.14. A method of recovering a cleaning agent, the cleaning agent havingbeen used for removing, through contact with a harmful gas, a silane gascontained as a harmful component in the harmful gas, and containingcopper oxide and manganese oxide as components thereof, the methodcomprising: immersing the cleaning agent in an acidic solution, tothereby transform a copper component and a manganese component to asoluble copper salt and a soluble manganese salt, respectively, andcause a silicon component to precipitate in the form of silicon oxide,the silicon component having been sorbed in the cleaning agent duringthe course of cleaning the harmful gas; separating the silicon componentfrom the copper component and the manganese component; adding aprecipitant for copper and manganese to the solution from which thesilicon component has been removed, to thereby cause a copper compoundand a manganese compound to precipitate; and recovering the coppercomponent and the manganese compound of the cleaning agent.
 15. A methodof recovering a cleaning agent according to claim 14, wherein hydrogenperoxide is added to the acidic solution upon or after immersion of thecleaning agent which has been used, to thereby enhance solubility ofmanganese in the solution and improve solidification of silicon.
 16. Amethod of recovering a cleaning agent according to any one of claims 12to 14, wherein, after formation of precipitates of the copper compoundand the manganese compound, the copper component and the manganesecomponent contained in the precipitates are recovered in the form ofcopper oxide and manganese oxide.
 17. A method of recovering a cleaningagent according to claim 16, wherein the copper oxide which is recoveredhas a BET specific surface area of 10 m²/g or more.
 18. A method ofrecovering a cleaning agent according to claim 16, wherein the manganeseoxide which is recovered has a BET specific surface area of 50 m²/g ormore.
 19. A method of recovering a cleaning agent according to any oneof claims 12 to 14, wherein the precipitant for copper and manganese isat least one species selected from among lithium hydroxide, sodiumhydroxide, potassium hydroxide, ammonium hydroxide, sodium carbonate,potassium carbonate, ammonium carbonate, sodium hydrogencarbonate,potassium hydrogencarbonate, and ammonium hydrogencarbonate.
 20. Amethod of recovering a cleaning agent according to any one of claims 12to 14, wherein a reducing agent is added to the acidic solution upon orafter immersion of the cleaning agent which has been used, to therebyenhance solubility of manganese in the solution.
 21. A method ofrecovering a cleaning agent according to any one of claims 12 to 14,wherein the cleaning agent containing copper oxide and manganese oxidefurther contains, before use of the agent, at least one species selectedfrom a metal and a metal oxide other than copper oxide and manganeseoxide.
 22. A method of recovering a cleaning agent according to any oneof claims 12 to 14, wherein manganese oxide contained as a componentthereof in the cleaning agent before use has a BET specific surface areaof 50 m²/g or more.
 23. A method of recovering a cleaning agentaccording to any one of claims 1, 2, 12, 13, and 14, wherein copperoxide contained as a component thereof in the cleaning agent before usehas a BET specific surface area of 10 m²/g or more.
 24. A method ofrecovering a cleaning agent according to claim 2 or 13, wherein theprecipitant for phosphorus is at least one species selected from amongmagnesium chloride, calcium chloride, magnesium sulfate, magnesiumnitrate, and calcium nitrate.
 25. A method of recovering a cleaningagent according to any one of claims 1 to 3 and 12 to 14, wherein theacidic solution is sulfuric acid, nitric acid, or hydrochloric acid. 26.A method of recovering a cleaning agent according to any one of claims 1to 3 and 12 to 14, wherein the cleaning agent before use has a BETspecific surface area of 10 m²/g or more.